We provide 3 sets of conversion factors:
Most frequently requested. An abridged version of the full set: the reduced volume of information makes it easier to find the factors you need. Recommended for most, and new, users of conversion factors.
All available factors for the selected year: recommended for advanced users only due to the volume of information.
Flat file set
Same information as the full set, but arranged for automated processes. Available from 2014 onwards. Not recommended for most users.
The methodology paper, due to be published here in late July, explains how the conversion factors are derived.
For new users of the conversion factors, we recommend you download the condensed set of conversion factors from the latest available year and read the guidance in the document’s introductory sheet. Then follow the informative text at the top of each conversion factor tab in the output files.
For repeat users of the conversion factors we suggest that you download your preferred factor set and read the ‘what’s new’ sheet before using the conversion factors. This highlights the most significant changes to the conversion factors made in this update. Following the ‘what’s new’ guidance ensures that reporting is consistent and comparable year-on-year.
Defra’s Environmental reporting guidelines provides more detail.