Sourcing, revisions, corrections and disclosure.
Reference tables are built from official standards bodies, public price lists, platform documentation or named open datasets, linked at the bottom of each page with the date we checked them. We do not print values we cannot source.
Reference pages are living documents: when a standard, spec or fee changes, we revise the existing page rather than publish a new one. Each page shows its original date and the date of the last revision.
Any calculation we publish shows the formula alongside the result, with the assumptions stated. Where inputs genuinely vary by store, we show the range and how to plug in your own numbers.
Errors are corrected on the page with a dated note. Request a correction at [email protected].
Some links may earn the publication a commission. Commissions never decide what goes in a table or how items are ordered; tables follow the published standards and numbers.