With the goal of harmonising the calculation of MRLs across the OECD, the OECD has developed a MRL Calculator. It is made up of an Excel spreadsheet which is simple to use and deosn't require extensive statistical knowledge from the user. There is one spreadsheet for single data sets and one spreadsheet for multiple data sets. A User Guide and a Statistiscal White Paper are available to help with the use of the Calculator.
The OECD MRL Calculator Spreadsheets have been revised in Version 2 to address a known issue with precision of computer-based floating point arithmetic. The resulting discrepancies could result in selection of an incorrect rounded MRL recommendation in the rare instance that the unrounded MRL falls exactly on the transition between rounding classes. This has been corrected by implementing the round() function in the final calculation. Version 2 also updates the files to XML format, which is compatible with Excel 2007 and later.
The OECD MRL Calculator Spreadsheets Version 2 were made publicly available on 23 April 2020.