Transparency

Data sources and licenses

Tax rules are taken from primary sources only — statutes, revenue procedures and tax authorities' own publications. Statistical data and design assets are used under the licenses below. This page is the single place where we credit them.

Tax rules

Tax rules are facts published by governments; we reimplement them in our own code. Official documents are public records of the issuing authority.

Statistical data

Percentiles, price levels and inflation series will be listed here with their licenses as each dataset is added.

Maps, icons, typefaces and software