Students in OECD countries and economies receive an average of 7 642 hours of compulsory instruction during their primary and lower secondary education, ranging from 5 304 hours in Poland to double that in Australia (11 000 hours).
Across OECD countries and economies, compulsory instruction time for primary students averages 804 hours per year, while lower secondary students receive an average of 118 more hours of compulsory education per year (922 hours).
On average across OECD countries and economies, instruction in reading, writing and literature and in mathematics represents 41% of compulsory instruction time for primary school students, but only 27% of compulsory instruction time for lower secondary school students.
Education at a Glance 2025
OECD Indicators
Context
Providing instruction in formal classroom settings accounts for a large portion of public investment in education. Countries make various choices about the overall amount of time devoted to instruction and which subjects are compulsory. These choices reflect national and/or regional priorities and preferences concerning what material students should be taught and at what age. Almost all countries have statutory or regulatory requirements regarding hours of instruction. These are most often stipulated as the minimum number of hours of instruction a school must offer and are based on the understanding that sufficient time is required for good learning outcomes.
Matching resources with students’ needs and making optimal use of time are central to education policy. Teachers’ salaries, institutional maintenance and the provision of other educational resources constitute the main costs of education. The length of instruction time (as partly covered in this chapter) is an important factor in determining how funds for education are allocated [see factors influencing the salary cost of teachers per student in Chapter D4, and the allocation of funding to schools in Chapter D6 in OECD (2021[1])].
There is growing awareness of the importance of time spent outside the classroom during the school day in activities other than instruction, including recesses and breaks. In addition to formal instruction time, students may participate in extracurricular activities before and/or after the school day or during school holidays, but these activities (as well as examination periods) are outside the scope of this chapter. For information about the relationship between instruction time and time dedicated to homework see OECD (2023[2]; 2014[3]).
In hours, in primary and lower secondary education, in public institutions
Note: In this figure instruction hours for each grade refer to average hours per grade for the level of education. Numbers in square brackets refer to the total number of years for primary and lower secondary education.
1. Year of reference: 2024.
2. The number of grades in lower secondary education is three or four, depending on the track. The fourth year of pre-vocational secondary education was excluded from the calculation.
3. Estimated number of hours by level of education based on the average number of hours per year, as for some subjects, the allocation of instruction time across multiple levels is flexible.
For data, see Table D1.1. For a link to download the data, see Tables and Notes section.
Other findings
Primary education lasts six years on average across OECD countries and economies, ranging from four to seven years. Lower secondary education lasts three years on average across OECD countries and economies, ranging from two to six years. In three out of five OECD and partner countries and economies, at least one year of upper secondary education is part of compulsory full-time general education.
On average across OECD countries and economies, the number of instruction days per year is similar at primary (186 days), lower secondary (184 days) and upper secondary levels (183 days). The difference in the number of instruction days per year between primary and lower secondary levels is less than two days in most countries, but is ten days (two weeks) or more in Bulgaria, Ireland, Lithuania, and Luxembourg.
An average of 1% of compulsory instruction time for primary students and lower secondary students is devoted to compulsory subjects with a flexible timetable in OECD countries and economies (excluding a few countries where the compulsory curriculum is mostly devoted to subjects with a flexible timetable). An average of 3% of compulsory instruction time both at the primary level and at the lower secondary level is devoted to flexible subjects chosen by schools.
In more than one-quarter of countries with available data, the allocation of instruction time across grades is flexible, with the instruction time for a specific subject defined for a certain number of grades or even the whole of compulsory education, without specifying how much time is to be allocated to each grade.
Compulsory general education
Both annual instruction time and the length of compulsory education have an impact on the total instruction time during compulsory education. In some countries, the duration of compulsory education is shorter and students face a heavier annual workload to meet on statutory requirements. In other countries, the workload is distributed over more years. This chapter focuses on compulsory education at primary and lower secondary levels (in public institutions). However, in 23 OECD and partner countries, at least one year of pre-primary education is also compulsory, so the starting age for compulsory education is below the age at which primary education starts (see Figure D.D1.1 in Education at a Glance 2025 Sources, Methodologies and Technical Notes (https://doi.org/10.1787/fcfaf2d1-en) for more details on the number of years of compulsory education). Moreover, in around three-fifths of countries and economies with available data, at least one year of upper secondary education is part of compulsory full-time education (Table D1.1).
In nearly three out of four countries and economies with available data, students are required to start primary education at the age of 6. In most other countries, students are not required to start until they are 7 (in Bulgaria, Croatia, Estonia, Finland, Latvia, Lithuania, Poland and Sweden). Only in Australia, England (United Kingdom), New Zealand and Scotland (United Kingdom) does start primary education at age 5 (Table D1.2).
There is also substantial variation in the duration of primary education. On average across OECD countries and economies, primary education lasts six years, but it ranges from four years in Austria, Bulgaria, Croatia, Germany, Hungary, Lithuania, Poland, the Slovak Republic and the Republic of Türkiye to seven years in Australia, Denmark, Iceland, Norway and Scotland (United Kingdom). Compulsory lower secondary education averages three years, but ranges from two years in Chile and the Flemish and French Communities of Belgium to five years in Germany, Peru and the Slovak Republic, and six years in Lithuania (Table D1.2). However, the number of grades allocated to each level of compulsory education may differ within countries, across subnational entities, for example in federal countries such as the United States (Box D1.2).
Countries allocate annual instruction time differently over the year. The number of instruction days and the way they are distributed across the school year can vary significantly between countries, as countries organise holidays differently (Box D1.1). The distribution of instruction time during the week also varies between countries. For example, whereas students go to primary and lower secondary school five days per week in nearly all countries, in Belgium and France, students typically do not go to school one half-day, usually on Wednesday afternoon (see Box D1.2 in OECD (2019[4])). Countries also vary in the way they organise recess and breaks within the school day (see Box D1.2 in OECD (2018[5])).
The length of the school year varies greatly between countries, implying that there is also wide variation in the number of weeks students are not at school across countries. Countries organise the school year in different ways, in terms of the frequency and length of school breaks during the school year.
In about three-quarters of the 40 OECD countries and economies, the total length of school breaks is harmonised for the whole country, and ranges from less than 12 weeks in Costa Rica to more than 18 weeks in Latvia, with an average of 13 weeks. However, the distribution of breaks during the school year can be flexible across subnational entities. For example, dates for school breaks are defined according to three zones in France, and there is similar flexibility in Austria, the Netherlands, Poland, the Slovak Republic and Slovenia (see Figure D.D1.2 in Education at a Glance 2025 Sources, Methodologies and Technical Notes (https://doi.org/10.1787/fcfaf2d1-en) for the organisation of the school year at primary level).
In the remaining one-quarter of countries and economies, the total length and the distribution of school breaks can differ between subnational entities (especially in federal countries) and/or individual schools (e.g. in Italy), even if decisions related to these school breaks need to be taken following some higher-level guidelines. For example, schools in Italy autonomously organise school breaks under regional guidelines.
In all countries, the longest break is the one between two successive school years. This break ranges from 3 weeks in some cantons in Switzerland to 12 weeks or more in Bulgaria, Chile (in some subnational entities due to specific climatic conditions), Greece, Italy and Latvia. In nearly all countries with available information, this break between two school years represents at least half of the school holiday time (Figure D1.2)
In addition to this long break, students usually have two to four other shorter holiday periods during the school year. England (United Kingdom) and Luxembourg as well as some Länder in Germany and some Canton in Switzerland offer a fifth break (Figure D1.2).
common break period, corresponding to either an approximately two-week break (in the northern hemisphere) or the end of the school year break in the southern hemisphere.
In most countries, the length of the different breaks within the school year varies, from a few days to more than two weeks. Exceptions to this pattern are France, the French Community of Belgium and New Zealand with consistent two-week breaks. Several countries and economies (the Flemish Community of Belgium, Czechia, Costa Rica, England [United Kingdom], Estonia, Ireland, Latvia, Luxembourg, the Netherlands, Scotland [United Kingdom] and Türkiye) alternate one-week and two-week breaks during the school year (Figure D1.2).
In weeks, in public institutions
Note: Breaks exclude public/religious days, except if these days are included in longer breaks.
1. End-of-year break includes examination periods.
2. Minimum length of breaks. Length of breaks may vary by region, by programme and/or by individual school.
3. Data for the federal state with the highest number of pupils, Nordrhein-Westfalen. The length and number of breaks for Germany are indicative due to variation across Länder, even if the total duration of breaks is similar across the Länder.
4. Length of breaks may vary by region.
For a link to download the data, see Tables and Notes section.
Breaks during the school year differ in both length and timing, but the end of calendar year is the main
In most countries, the organisation of breaks is usually similar at primary and lower secondary levels. However, breaks at the end of the school year are shorter at lower secondary level than at primary level by two weeks in Lithuania. In contrast, they are about two weeks longer than at primary level in Portugal and four weeks longer in Ireland (see Figure D.D1.3 in Education at a Glance 2025 Sources, Methodologies and Technical Notes (https://doi.org/10.1787/fcfaf2d1-en) for the organisation of school year at the lower secondary level).
Intended instruction time
Intended instruction time is the total number of hours during which schools are obliged to offer instruction in compulsory and, if applicable, non-compulsory subjects. However, intended instruction time can be different from actual instruction time.
In most countries, the total statutory number of hours of intended and/or compulsory instruction time is defined at the national level (i.e. uniform across the country). The total statutory number of hours of intended and/or compulsory instruction time are defined at the subnational level in some federal countries (e.g. Belgium, Canada, Germany and the United States) and in some countries with a decentralised education system (e.g. Spain and the United Kingdom) (Box D1.2).
Even if all children within a country are enrolled in compulsory education for the same number of years, they do not necessarily receive the same amount of instruction time across the country. Subnational data provided by five countries (for 2025 for Belgium, Spain and the United Kingdom, 2024 for Canada, and 2023 for the United States) show how instruction time can vary significantly across subnational entities within a single country.
In four of these countries, the number of grades in primary and lower secondary education is the same for all subnational entities (Belgium, Canada, Spain and the United States). In the United Kingdom, the total number of grades at the primary and lower secondary levels differs by one year between England and Scotland. Primary education ranges from six years (in England) to seven years (in Scotland), while lower secondary is three years for both. As the number of grades of compulsory education at upper secondary level also varies between 1 and 2 years, the total length of compulsory education is 11 years in both.
Despite the similar number of grades at the subnational level in most countries, the number of compulsory instruction hours varies at the subnational level to different degrees. At the primary level, the number of compulsory instruction hours per year varies by less than 1% in Belgium (from 821 hours in the Flemish Community to 826 hours in the French Community), by 4% in Spain (from 788 hours in most subnational entities to 823 hours in the Comunidad Foral de Navarra) and by 75% in the United States (from an estimated minimum of 720 hours in New Jersey to 1 260 hours in Texas). In Canada, the number of intended instruction hours (compulsory and non-compulsory instruction time) varies by 14% at the primary level (from 837 hours in Nova Scotia to 950 hours in Alberta and Saskatchewan). These variations can add up to significant differences in the total number of hours of instruction over the whole course of primary education. Variations range from a total difference of 28 hours of compulsory instruction between the French and Flemish Communities in Belgium to 210 hours in Spain and 3 240 hours in the United States. In Canada, the difference in intended instruction time at the primary level reaches 680 hours.
The differences are similar at the lower secondary level: the annual number of compulsory instruction hours varies by about 2% in Spain, 7% in Belgium and 75% in the United States. Differences in the total number of compulsory instruction hours at the lower secondary level between subnational entities range from 70 hours in Spain to 129 hours in Belgium and 1 620 hours in the United States. In Canada, the number of intended instruction hours varies by about 6% (168 hours) between the different provinces at the lower secondary level.
The extent of these variations may reflect differences in the number of annual days of instruction at both the primary and lower secondary levels, except in Spain, where the number of instruction days does not vary across subnational entities. The annual number of instruction days at the primary level varied by 1% in Belgium (1 day, from 176 days in the Flemish Community to 177 days in the French Community), 6% in Canada (10 days, from 180 days in Quebec to 190 days in Saskatchewan) and 16% in the United States (26 days, from 160 days in Colorado to 186 days in Kansas). Similar differences are found at the lower secondary level.
Source: Education at a Glance Database, https://data-explorer.oecd.org/.
Instruction may also occur outside compulsory school hours and outside the classroom or school, which is not covered in this chapter. In some countries, lower secondary school students are encouraged to take after-school classes in subjects already taught in school to help them improve their performance. Students can participate in after-school lessons in the form of remedial catch-up classes or enrichment courses, with individual tutors or in group lessons provided by school teachers, or in other independent courses (see Box D1.2 in OECD (2017[6]) and notes on the organisation of the school day in Education at a Glance 2025 Sources, Methodologies and Technical (https://doi.org/10.1787/fcfaf2d1-en) for more information).
Compulsory instruction time
Compulsory instruction time refers to the amount and allocation of instruction time that must be provided in almost every public school and must be attended by almost all public sector students, in line with public regulations.
Across OECD countries and economies, total compulsory instruction time in primary and lower secondary general education averages 7 642 hours spanning across 9 years on average. This ranges from 5 304 hours in Poland (over 8 years) to 11 000 hours in Australia (over 11 years) (Figure D1.1). In England (United Kingdom), New Zealand and Scotland (United Kingdom), the regulations do not prescribe compulsory instruction time in schools. However, schools are required to be open for instruction for a minimum number of hours per day (New Zealand) or to allow sufficient instruction time to deliver a broad and balanced curriculum that includes all statutory requirements (England and Scotland [United Kingdom]).
Breaking it down by level, on average across OECD countries and economies, students receive 4 560 hours of compulsory instruction over 6 years of primary education and 3 082 hours during 3 years of lower secondary general education. The average annual number of compulsory instruction hours tends to increase with level of education in most countries (from 804 hours in primary education to 922 hours in lower secondary general programmes on average across OECD countries and economies), except in Costa Rica (where there is a 2% decrease in hours between primary and lower secondary), Luxembourg (9% decrease) and Portugal (6% decrease) (Table D1.1).
Compulsory instruction time per year generally increases with age, averaging 779 hours at age 7, 843 hours at age 10, then 929 hours at age 13. In Bulgaria, Croatia, Czechia, Korea, Latvia, Mexico, Poland and Romania, the average annual number of compulsory instruction hours increases by more than 40% between ages 7 and 13 (Table D1.5, available on line).
Compulsory instruction time, by definition, only captures the time spent by students in formal classroom settings (as established in public regulations). It does not show the actual number of hours of instruction that students receive and does not cover learning outside the formal classroom setting. In addition, compulsory instruction time does not always reflect the evolving demand of societies, such as rapid technological transformation. Education systems are increasingly expected to equip students for the future, like essential digital competences (see Box D1.3).
Modern society is transforming rapidly with the development and use of innovative technologies. Countries adapt their education systems and their curricula to technological evolution to ensure they are giving students essential skills to prepare them for this digital transformation and to succeed in the future. Schools progressively integrate digital competence (which encompasses a set of skills, knowledge and attitudes) into the curriculum, for example with digital literacy, coding, and the effective use of digital tools for learning and teaching. However, the definition of digital competence and how it is implemented in compulsory education differ across countries (OECD, 2023[7]; EACEA: Eurydice, 2019[8]; EACEA: Eurydice, 2023[9]).
Digital competence can be taught in three ways: 1) as a separate subject in the curriculum (as a compulsory or optional subject); 2) integrated with specific subjects of instruction (components of digital competence are then integrated within a compulsory subject); or 3) as a cross-curricular subject (defined as transversal and therefore integrated along with all compulsory subjects, teachers being responsible for developing it). In nearly two-thirds of European countries the cross-curricular approach is implemented in primary education and in more than half of these countries it is also implemented in secondary education. Nevertheless, it is common for European education systems to combine two of these curriculum approaches, and in one-third of these systems, all three approaches are integrated in at least one level of education (EACEA: Eurydice, 2023[9]).
Czechia is one country combining the three approaches for teaching digital competences. Recent reforms to implement the new informatics curriculum at the primary level (since 2023) and at the lower secondary level (in the 2024/25 school year), make informatics a separate compulsory subject from the fourth to ninth grade. Many other European countries have been undertaking similar reforms to integrate digital competence into their education system (EACEA: Eurydice, 2023[9]). In addition to these reforms, 26 OECD countries and economies, as well as Brazil, have established rules or guidelines to incorporate digital competence as a transversal competence within the curriculum (these being applied mostly to all levels of education) (OECD, 2023[7]).
However, to ensure that students are efficiently prepared to develop digital competences, teachers need to be sufficiently trained in this area. A recent OECD survey has raised concerns about the gap between teachers’ actual training and classroom practices. Creating a wider ecosystem approach would be beneficial to ensure the equitable development of students and teachers in digital competences. Providing support and professional development to teachers would also help students to better adapt and effectively face the technological evolution to come (OECD, 2023[7]; EACEA: Eurydice, 2023[9]).
Non-compulsory instruction time
In about three out of five countries and economies with available data, there is no non-compulsory instruction time, so intended and compulsory instruction time are the same (i.e. intended instruction time is fully compulsory) for primary and lower secondary students. In the remaining countries and economies, intended instruction time includes both compulsory instruction time and a specified amount of non-compulsory instruction time (which must be provided in almost every public school, but which is not mandatory for almost all students in public schools): eight countries at primary level and nine at lower secondary level (Table D1.1).
Among countries with available data, non-compulsory instruction time is equivalent to more than 20% of compulsory instruction time in a few countries. At the primary level, non-compulsory time is equivalent to 20% of total compulsory instruction time in Slovenia, 25% in Croatia and 53% in Greece. At the lower secondary level, non-compulsory time is equivalent to 20% in Croatia, about 22% of total compulsory instruction time in France, 23% in Slovenia and 30% in Greece (Table D1.3 and Table D1.4). However, these values need to be interpreted with caution. In France, for example, lower secondary students are offered a wide variety of courses in the non-compulsory curriculum, and they could not physically attend all the subjects and hours available.
Instruction time per subject
On average across OECD countries and economies, 41% of the compulsory instruction time at primary level is devoted to providing students with fundamental skills in literacy and numeracy: 25% on reading, writing and literature and 16% on mathematics. In Croatia and France, at least half of compulsory instruction time is allocated to reading, writing and literature (first language) and mathematics (Ireland and Luxembourg could also be included in the list as instruction time on second language includes other national languages). Together with arts (11%), physical education and health (10%), natural sciences (7%), second and other languages (7%), and social sciences (6%), these seven study areas form more than 80% of compulsory instruction time on average across OECD countries and economies where instruction time per subject is specified (Table D1.3 and Figure D1.3).
Religion, ethics and moral education; information and communication technologies (ICT); technology; practical and vocational skills; and other subjects make up the remainder of the non-flexible compulsory curriculum at the primary level, representing about 13% of the compulsory instruction time on average across the OECD (Table D1.3).
At the lower secondary level, the seven major study areas at the primary level continue to take up the major part of the compulsory curriculum (79%), but as the curriculum generally becomes more subject specific the way this time is allocated changes significantly. On average across the OECD countries and economies where instruction time per subject is specified, reading, writing and literature (14%) and mathematics (13%) make up 27% of the compulsory curriculum, 14 percentage points lower than that in primary education. The shares allocated to physical education and health (8%) and to the arts (7%) are also lower than at the primary level. Conversely, the proportions of compulsory instruction time devoted to natural sciences climbs from 7% to 12%, to social sciences from 6% to 11%, and to second and other languages from 7% to 14%. Religion, ethics and moral education; ICT; technology; practical and vocational skills; and other subjects make up the remainder of the non-flexible compulsory curriculum for lower secondary students (about 13% of the total compulsory instruction time) (Figure D1.3, and Table D1.3 and Table D1.4).
Percentage of total compulsory instruction time, in public institutions
Note: Some subject categories include subjects in different categories. See source table for details.
1. The second language of instruction includes other national languages taught.
2. Reading, writing and literature includes social sciences (at primary level in Israel, at lower secondary level in Italy).
3. Year of reference: 2024.
4. The Flemish Community of Belgium, the French Community of Belgium, Ireland (lower secondary), Italy (primary), the Netherlands, Poland (primary) and Portugal (primary) are not included in the averages.
5. Mathematics includes natural sciences.
6. Excludes the last year of primary education (first four years of primary school) for which the instruction time is allocated to specific compulsory subjects.
For data, see Table D1.3 and Table D1.4. For a link to download the data, see Tables and Notes section.
At the lower secondary level, there is substantial variation in how countries allocate time to the different subjects within the compulsory curriculum. For example, reading, writing and literature account for 12% or less of compulsory instruction time in Costa Rica, Czechia, Finland, Hungary, Israel, Japan, Luxembourg, Peru and Sweden but more than 25% of compulsory instruction time in Greece and Italy (in Italy, this also includes time devoted to social sciences). In Ireland, reading, writing and literature are taught in two national languages and therefore the combined instruction time for the two languages reaches around 17% of the total compulsory instruction time. Natural sciences account for 10% or less of compulsory instruction time in the French Community of Belgium, Iceland, Luxembourg and Norway, but 20% or more of compulsory instruction time in Estonia and Korea (in Korea, this also includes time devoted to ICT, technology, and practical and vocational skills). Compulsory instruction time devoted to second and other languages also varies widely between countries. Second-language instruction accounts for 7% or less of compulsory instruction time in Costa Rica, Greece and Romania and 13% or more in the French Community of Belgium, Iceland, Japan, Latvia and Luxembourg. In addition, more than four out of ten countries with available data allocate some compulsory instruction time for lower secondary students to instruction in another language in addition to a second language (Figure D1.3, and Table D1.3 and Table D1.4).
As the difference between the primary and lower secondary levels shows, there are significant differences in how time is allocated to school subjects as students grow older. For example, on average across OECD countries, 28% of instruction time is devoted to reading, writing and literature for 7-year-olds, 19% for 11-year-olds and 12% for 15-year-olds. In contrast, while an average of 4% of instruction time for 7-year-olds is devoted to a second language, 11% of instruction time for 11-year-olds is spent studying a second language and 1% studying other languages, while for 15-year-olds, the percentages are 10% for a second language and 4% for other languages. The proportion of instruction time devoted to other subjects also changes, as explored in Table D1.6 (available on line).
Flexibility in the curriculum
In most countries and economies, central and state authorities establish regulations or recommendations regarding instruction time and the curriculum. However, local authorities, schools, teachers and/or students also have varying degrees of freedom in organising instruction time or in choosing subjects.
In at least one-quarter of countries and economies with available data, the allocation of instruction time is vertically flexible in primary and lower secondary general education, meaning that instruction time for a specific subject is defined for a certain number of grades or even the whole of compulsory education, without specifying the time to be allocated to each grade. In such cases, schools or local authorities are free to decide how much time should be allocated for each grade (Table D1.2).
In a few countries and economies, compulsory subjects are set within a horizontally flexible timetable for few or most subjects. This means that overall instruction time is defined for a certain number of compulsory subjects or even the whole of compulsory education, but the time to be allocated to each subject is not. In Portugal, more than half of the compulsory curriculum at the primary level is organised within a flexible timetable, and the share reaches 90% or more in the Flemish Community of Belgium and in Italy. In the Netherlands and Poland (in the first three grades), the entire curriculum at the primary level is organised as a flexible timetable. At the lower secondary level, similar patterns are found in the Flemish Community of Belgium and the Netherlands. In these countries and economies, local authorities, schools and/or teachers are free to decide how much time to allocate to most compulsory subjects. In Scotland (United Kingdom), at both primary and lower secondary levels, some compulsory subjects are specified, but there is no regulation on total instruction time, which is the responsibility of local authorities and schools themselves. Excluding these countries and economies, compulsory subjects with flexible timetables account for 1% of the compulsory instruction time at both primary and lower secondary levels, even if they are a significant part of the curriculum in some countries (Table D1.3 and Table D1.4).
More details on the different combinations of flexibility employed by countries, in both primary and lower secondary education, can be found in Box D1.4.
Flexibility in the choice of subjects is less common across OECD countries. On average, 3% of compulsory instruction time is allocated to subjects chosen by schools at the primary level. At the lower secondary level, 3% of compulsory instruction time is allocated to subjects chosen by schools and another 3% to subjects chosen by students. However, some countries and economies allocate a substantial part of the compulsory instruction time to flexible subjects. For example, about 10% or more of compulsory instruction time is allocated to subjects chosen by schools in Chile, Czechia, Estonia (primary), the Flemish Community of Belgium (lower secondary), Ireland (lower secondary), Israel (primary), the Slovak Republic (lower secondary) and Spain (lower secondary). In Iceland, Norway and Türkiye, 15-20% of compulsory instruction time is allocated to subjects chosen by lower secondary students (Table D1.3 and Table D1.4).
Subjects in the compulsory curriculum may be taught as specific individual subjects in the national curriculum with a specific time allocated to them by grade, or they may be taught as part of the curriculum without a specific amount of time allocated to them. In the second case, schools or local authorities are free to decide which compulsory subjects to prioritise and how much time should be assigned to teach a specific subject by grade (horizontal flexibility), or how much time should be allocated to a specific subject in each grade when the total instruction time for this subject is only defined for a group of grades (vertical flexibility). Figure D1.4 shows the combinations of both kinds of flexibility for countries and economies with available data for both primary and secondary level.
Note: Instruction time is flexible either when the number of hours of instruction is defined for a group of subjects rather than for each subject (horizontal flexibility) or when it is defined for a group of grades rather than for each grade (vertical flexibility). Countries and economies are not included in the category of flexibility for a few subjects if a subject is flexible for two grades or fewer (for each level of education).
1. Primary education and lower secondary education are in different categories of flexibility.
2. Two or more subjects are taught together at the national level.
3. Some autonomous communities have vertical flexibility in all subjects.
For data, see Table D1.1, Table D1.3 and Table D1.4.
Horizontal flexibility in the distribution of instruction time across subjects is the most common practice among countries and economies, in both primary and lower secondary education. Vertical flexibility is implemented in just 10 countries and economies at primary level and 12 at lower secondary. There is no flexibility, i.e. with specific instruction time allocated for both subjects and grades, in just 11 countries and economies each at both the primary and the lower secondary level.
In most education systems, only one type of flexibility is implemented in their national curricula at the primary level: in 17 countries instruction time is defined for groups of subjects in specific grades (horizontal flexibility only), while in Norway, instruction time for specific subjects is defined for several grades (vertical flexibility only). At the primary level, instruction time is defined for a combination of both subjects and grades in only nine countries (Czechia, Estonia, Finland, Iceland, Korea, Latvia, Lithuania, the Netherlands and Sweden).
Similar patterns are observed at the lower secondary level, although there are differences in horizontal flexibility between primary and lower secondary education. For instance, in Denmark, the French Community of Belgium and Türkiye, there is no flexibility in instruction time in primary education, but there is for some groups of subjects in lower secondary education. Conversely, instruction time is flexible for some groups of subjects in primary education, but not in lower secondary education in Croatia, Luxembourg and Poland.
In a few other countries (Ireland, Israel, Lithuania and Norway), the type of flexibility used in the allocation of instruction time varies between primary and lower secondary levels. At primary level, the curricula in Ireland and Israel only offer horizontal flexibility in instruction time and the curriculum in Norway only offers vertical flexibility, while all three combine both types of flexibility (at least for a few subjects) in lower secondary education. Conversely in Lithuania, both types of flexibility are used at the primary education level, while only vertical flexibility is implemented for the definition of instruction time in lower secondary education.
Compulsory instruction time/curriculum refers to the amount and allocation of instruction time that has to be provided in almost every public school and must be attended by almost all public sector students. The compulsory curriculum may be flexible, as local authorities, schools, teachers and/or students may have varying degrees of freedom to choose the subjects and/or the allocation of compulsory instruction time.
Compulsory flexible subjects chosen by schools refers to the total amount of compulsory instruction time indicated by the central authorities which regional authorities, local authorities, schools or teachers allocate to subjects of their choice (or subjects they chose from a list defined by central education authorities). It is compulsory for the school to offer one of these subjects, and students must attend.
Compulsory options chosen by the students refers to the total amount of instruction time in one or more subjects that students have to select (from a set of subjects that are compulsory for schools to offer) in order to cover part of their compulsory instruction time.
Compulsory subjects with a flexible timetable refers to the total amount of instruction time indicated by the central authorities for a given group of subjects which regional authorities, local authorities, schools or teachers allocate to individual subjects. There is flexibility in the time spent on a subject, but not in the subjects to be taught.
Flexible allocation of instruction time across multiple grades refers to the case where the curriculum only indicates the total instruction time for a specific subject for a certain number of grades, or even the whole of compulsory education, without specifying the time to be allocated to each grade. In such cases, schools/local authorities are free to decide how much time should be assigned for each grade.
Instruction time refers to the time a public school is expected to provide instruction to students on all the subjects integrated into the compulsory and non-compulsory curriculum, on school premises or in before-school/after-school activities that are formal parts of the compulsory programme. Instruction time excludes breaks between classes or other types of interruptions, non-compulsory time outside the school day, time dedicated to homework activities, individual tutoring or private study and examination periods (days for non-school-based examinations, e.g. national examinations).
Intended instruction time refers to the number of hours per year of the compulsory and non-compulsory part of the curriculum that students are entitled to receive in public schools. The intended curriculum can be based on regulations or standards of the central (or top-level) education authorities or may be established as a set of recommendations at the regional level.
The non-compulsory part of the curriculum refers to the total amount of instruction time that public schools must offer on top of the compulsory instruction time, but which is not mandatory for all students. Subjects can vary from school to school or from region to region and take the form of optional subjects. Additional activities before/after classes offered by the school are not per se part of the non-compulsory curriculum; for instance, if there is no obligation upon public schools to provide this instruction time or it is not part of the official curricula. In particular, non-compulsory education excludes morning care classes or after-school care classes, even if they are officially regulated.
This chapter captures intended instruction time (as established in public regulations) as a measure of learning in formal classroom settings. It does not show the actual number of hours of instruction that students receive and does not cover learning outside of the formal classroom setting. Differences may exist across countries between the regulatory minimum hours of instruction and the actual hours of instruction received by students. Given such factors as school timetables, lesson cancellations and teacher absenteeism, schools may not consistently attain the regulatory minimum instruction time (see Box D1.1 in OECD (2007[10])).
This chapter also illustrates how minimum (and/or recommended) instruction hours are allocated across different curricular areas. It shows the intended net hours of instruction for those grades that are part of compulsory full-time general education. Although the data are difficult to compare among countries because of different curricular policies, they nevertheless provide an indication of how much formal instruction time is considered necessary for students to achieve the desired educational goals.
When the allocation of instruction time across grades is flexible (i.e. instruction time for a specific subject is defined for a certain number of grades, or even the whole of compulsory education, without specifying the time to be allocated to each grade), instruction time per age or level of education was estimated by assuming equal distribution of the total number of instruction hours between grades.
For more information please see the OECD Handbook for Internationally Comparable Education Statistics (OECD, 2018[11]) and Education at a Glance 2025 Sources, Methodologies and Technical Notes (https://doi.org/10.1787/fcfaf2d1-en).
Data on instruction time are from the 2024 Joint Eurydice-OECD Instruction time data collection and refer to instruction time during compulsory primary and full-time (lower and upper) secondary general education for the school year 2024/25. Data on school calendars are from the 2024 Joint Eurydice-OECD data collection on school calendars and refer to dates on holiday periods for students at primary and (lower and upper) secondary education for the school year 2024/25.
References
[9] EACEA: Eurydice (2023), Structural Indicators for Monitoring Education and Training Systems in Europe 2023: Digital Competence at School, Publications Office of the European Union, Luxembourg, https://data.europa.eu/doi/10.2797/886074.
[8] EACEA: Eurydice (2019), Digital Education at School in Europe, Publications Office of the European Union, Luxembourg, https://data.europa.eu/doi/10.2797/763.
[7] OECD (2023), OECD Digital Education Outlook 2023: Towards an Effective Digital Education Ecosystem, OECD Publishing, Paris, https://doi.org/10.1787/c74f03de-en.
[2] OECD (2023), PISA 2022 Results (Volume II): Learning During – and From – Disruption, PISA, OECD Publishing, Paris, https://doi.org/10.1787/a97db61c-en.
[1] OECD (2021), Education at a Glance 2021: OECD Indicators, OECD Publishing, Paris, https://doi.org/10.1787/b35a14e5-en.
[4] OECD (2019), Education at a Glance 2019: OECD Indicators, OECD Publishing, Paris, https://doi.org/10.1787/f8d7880d-en.
[5] OECD (2018), Education at a Glance 2018: OECD Indicators, OECD Publishing, Paris, https://doi.org/10.1787/eag-2018-en.
[11] OECD (2018), OECD Handbook for Internationally Comparative Education Statistics 2018: Concepts, Standards, Definitions and Classifications, OECD Publishing, Paris, https://doi.org/10.1787/9789264304444-en.
[6] OECD (2017), Education at a Glance 2017: OECD Indicators, OECD Publishing, Paris, https://doi.org/10.1787/eag-2017-en.
[3] OECD (2014), “Does homework perpetuate inequities in education?”, PISA in Focus, No. 46, OECD Publishing, Paris, https://doi.org/10.1787/5jxrhqhtx2xt-en.
[10] OECD (2007), Education at a Glance 2007: OECD Indicators, OECD Publishing, Paris, https://doi.org/10.1787/eag-2007-en.
To download the data for the figures and tables in this chapter, click StatLink above.
To access further data and/or other education indicators, please visit the OECD Data Explorer: https://data-explorer.oecd.org/https://data-explorer.oecd.org/.
Data cut-off for the print publication 13 June 2025. Please note that the Data Explorer contains the most recent data.
Table D1.1. Instruction time in compulsory general education (2025)
Note: Columns showing the combined instruction time for compulsory primary and lower secondary education (i.e. Columns 15 to 18) and compulsory upper secondary education (i.e. Columns 19 to 25) are available for consultation on line.
1. Refers to full-time compulsory education and excludes pre-primary education, even if compulsory.
2. Estimated number of hours by level of education based on the average number of hours per year, as for some subjects, the allocation of instruction time across multiple levels is flexible.
3. Year of reference: 2024.
4. Excludes the last year of compulsory education, which can be classified at either the lower secondary or the upper secondary level.
5. The number of grades in lower secondary education is three or four, depending on the track. The fourth year of pre-vocational secondary education was excluded from the calculation.
Table D1.2. Organisation of compulsory general education (2025)
Note: Students go to school five days a week (six days in some schools in Israel and secondary education in Italy). In some countries, the statutory length of the school day varies within the school week. Columns showing the organisation of compulsory upper secondary education (i.e. Columns 9 to 12) are available for consultation on line.
1. Refers to full-time compulsory education and excludes pre-primary education, even if compulsory.
2. For some subjects, allocation of instruction time across multiple levels of education is flexible.
3. Year of reference: 2024.
4. Excludes the last year of compulsory education, which can be classified at either the lower secondary or the upper secondary level.
5. Flexible allocation of instruction time across three consecutive grades is applicable for grades 1, 4 and 7.
6. The number of grades in lower secondary education is three or four, depending on the track. The fourth year of pre-vocational secondary education was excluded from the calculation.
Table D1.3. Instruction time per subject in primary education (2025)
Note: The averages were adjusted to add up to 100% and do not correspond exactly to the average of each column. Please refer to Table D1.6, available on line, for instruction time per subject for each age.
1. For some subjects, allocation of instruction time across multiple levels of education is flexible.
2. Year of reference: 2024.
3. The second language of instruction includes other national languages taught.
4. The Flemish Community of Belgium, the French Community of Belgium, Italy, the Netherlands, Poland and Portugal are not included in the averages.
5. Excludes the last year of primary education (first four years of primary school) for which the instruction time is allocated to specific compulsory subjects.
Table D1.4. Instruction time per subject in general lower secondary education (2025)
Note: The averages were adjusted to add up to 100% and do not correspond exactly to the average of each column. Please refer to Table D1.6, available on line, for instruction time per subject for each age.
1. For some subjects, allocation of instruction time across multiple levels of education is flexible.
2. Year of reference: 2024.
3. The second language of instruction includes other national languages taught.
4. The Flemish Community of Belgium, the French Community of Belgium, Ireland and the Netherlands are not included in the averages.
a – category not applicable; b – break in series; d – contains data from another column; m – missing data; x – contained in another column (indicated in brackets). For further control codes, see the Reader’s Guide.
For further methodological information, see Education at a Glance 2025: Sources, Methodologies and Technical Notes (https://doi.org/10.1787/fcfaf2d1-en)].
By level of education, in public institutions
Note: For notes on this table and a link to download the data, see Tables and Notes section above.
By level of education, in public institutions
Note: For notes on this table and a link to download the data, see Tables and Notes section above.
As a percentage of total compulsory instruction time, in public institutions
Note: For notes on this table and a link to download the data, see Tables and Notes section above.
As a percentage of total compulsory instruction time, in public institutions
Note: For notes on this table and a link to download the data, see Tables and Notes section above.