Sources and data

No figure on calcswiss.ch is without an origin: every calculation parameter lives in a versioned data file that documents its own official source, retrieval date and tax year. The table below is generated directly from those data files — so it shows exactly the data the calculators on this site actually compute with.

Datasets in use

Each dataset name links to the official publication. The FTA tax data was obtained via the MIT-licensed reference implementationdevbrains/swisstaxcalculator, which builds on the same official dataset.

Publishing institutions

• Federal Tax Administration (FTA) — tax calculator and tax data
  Schedules, multipliers and deductions of the Confederation, cantons and municipalities
• Federal Statistical Office (FSO) — official register of municipalities
  FSO municipality numbers as the location key
• Federal Office of Public Health (FOPH) — health-insurance premiums
  Approved compulsory (KVG/LAMal) premiums by insurer, premium region, age group and franchise
• Federal Social Insurance Office (FSIO)
  AHV/IV/EO/ALV contribution rates, occupational-pension key figures and pillar 3a maximum amounts
• devbrains — swisstaxcalculator (MIT licence)
  Open-source reference implementation of the tax calculation based on FTA data; validation reference for our calculation logic

How we update the data

The calculators call no external APIs at runtime. All parameters are bundled at build time from the versioned data files; updates happen as traceable data refreshes with a new retrieval date. When an authority changes a value — the pillar 3a maximum amounts, say, or the multipliers of a new tax year — the affected file is renewed and the date in the table above moves with it. Every calculator page additionally states its data snapshot in the footer.

The calculation logic itself is covered by automated tests against published official example values; how we calculate is documented on the methodology page.

All calculations are indicative; the official assessment is binding. The FTA, FSO, FOPH and FSIO are not affiliated with this website.