The statistical goal of the OECD MRL Calculator is to produce an MRL proposal in the region of the 95th percentile of the underlying residue distribution (p95), which is conservative in the sense that it will have a much greater propensity to make errors by overestimating p95 than by underestimating it for most datasets.

The OECD MRL Calculator User Guide provides information about how to use the spreadsheets and how they work. It also describes examples to assist new users. The spreadsheets have been protected to avoid inadvertent changes to calculation formulas that may affect the results.

The OECD MRL Calculator Statistical White Paper explains the statistical approach of the methodology applied to develop the tool. It covers the types of residue datasets used to derive an MRL for pesticides and the challenges involved. It discusses the evolution of the OECD MRL Calculator and previous calculation methods. Finally, it explains tool's performance and provides examples of comparison between the MRLs produced by the OECD Calculator and other approaches. 

The OECD Residue Chemistry Expert Group (RCEG) and the Working Party on Pesticides are responsible for maintenance and new tool releases. The OECD MRL Calculator Spreadsheets have been revised in Version 2 to address a known issue with the precision of computer-based floating point arithmetic. The resulting discrepancies could result in the selection of an incorrectly rounded MRL recommendation in the rare instance that the unrounded MRL falls precisely 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.