How the Steuer-Zerleger calculates: methodology and test cases

The Steuer-Zerleger calculates Swiss taxes for all municipalities and shows where every franc comes from. This page explains where the data comes from, how the calculations are done and checked – and what is deliberately left out. All results are estimates without guarantee; the tax authority’s assessment is what counts.

01Data sources and dates

Income & wealth tax: Tax scales, tax coefficients of all municipalities including parishes, and deductions from the data export of the official tax calculator of the Swiss Federal Tax Administration (FTA), as of 2 October 2026 for the 2026 tax year and 11 June 2026 for 2025. Supplemented by official cantonal tables of tax coefficients for localities, school municipalities and parishes, districts and corrections. Personal and poll tax as in the FTA calculator, apart from the deliberate deviations below, with the legal basis for each canton. The flat-rate and social deductions of the gross-salary estimator come from the laws and information sheets of each canton, tax at source from the FTA tariff files for 2025 and 2026.
Pillar 3a & buy-ins: Maximum amounts and rules from the law, the ordinance and FTA circulars (BVG, BVV 3, DBG); the taxes themselves as for income tax and lump-sum withdrawals.
Pension or lump sum: Taxes as above; lifespans from the 2023 cohort life tables of the Federal Statistical Office (FSO), pension fund returns 2014 to 2025 from the data analysis of the Occupational Pension Supervisory Commission (OAK BV), OASI pensions 2026. Legal position checked on 3 November 2026.
Lump-sum withdrawal tax: Rate schedules for pension benefits from the FTA export, rules per canton from the ‘Kapitalleistungen’ volume of the ESTV ‘Steuermäppchen’ (as of 27 November 2025) and from laws and official directives, including the official conversion table for Ticino and Valais. Cross-checked on 7 November 2026.
Property gains tax: Laws, information sheets and official examples from all 26 cantons, researched and cross-checked up to 2 November 2026 (‘Advanced’ mode: 7 November 2026); tax coefficients from the FTA export.
Inheritance & gift tax: Laws, information sheets and official examples from all 26 cantons, as of 2 November 2026 (further relatives: 8 November 2026), municipal rates for Fribourg, Vaud, Lucerne and Graubünden.
Municipality ranking: the same data as for income tax; maps from the FSO (ThemaKart 2026) and from swisstopo (swissBOUNDARIES3D, official building address directory).

02How the calculations work

The basis is taxable income: entered directly or estimated from gross salary with the deductions of the canton and the Confederation. Direct federal tax follows the federal tax scale, on its own assessment basis. For the canton and municipality, the cantonal tax scale gives the simple tax; in most cantons, the canton, municipality and church each levy a percentage of it, the tax coefficient. Special cantonal rules – splitting and double scales for married couples, the family quotient in Vaud, the indexed scales in Valais, the formula in Geneva, church tax as a percentage of income in Uri and for Protestant (Reformed) and Christian Catholic church members in Basel-Landschaft – have been determined using the FTA calculator and checked for both tax years.

The calculator then breaks the tax down into brackets: for each income band it shows how many centimes per franc go to the Confederation, canton, municipality and church. The brackets add up exactly to the tax. The marginal tax rate is the slope of the tax scale at your point, without the steps caused by rounding to CHF 100.

Wealth follows the same pattern with the wealth tax scales; the Confederation levies no wealth tax. For lump-sum withdrawals, the Confederation applies one fifth of its tax scale, and the cantons use their own scale for pension benefits, a fraction of the income tax scale or the rate of an equivalent pension. Property gains and inheritances have their own calculation cores, built for each canton from the law and official examples.

All calculations take place exclusively in your browser. Your details are not transmitted to the server; the only exceptions are the canton abbreviation and, when you switch year, the selected tax year, for the anonymous usage count (see ‘Who is behind it’).

03Test cases in figures

Tolerance against the FTA calculator: CHF 2.50 per level (federal, cantonal, municipal, church). The FTA calculator rounds to whole francs. Some of the cases (holdout) were never used to tune the calculation, only for the final check. The test cases use the FTA calculator’s values; the deliberate deviations (below) apply in the result and are flagged there.

Income: 4,196 cases for 2026, 4,101 for 2025, all within the tolerance, largest deviation CHF 1.13. They include random incomes accurate to the franc, high incomes up to CHF 5 million, families with up to 9 children and, for 2026, 739 (2025: 736) cases for localities with their own tax coefficient.
Wealth: 834 cases for 2026, 912 for 2025, plus 201 and 202 holdout cases respectively, all within the tolerance; taxable wealth matches the FTA calculator in all cases.
Personal and poll tax: 200 random cases per year, all identical to the franc.
Lump-sum withdrawal tax: 11,693 municipal values from 581 cases for 2026, 9,474 from 390 for 2025, all 26 cantons, largest deviation CHF 0.77; holdout 1,520 and 1,526 municipal values respectively.
Internal checks: 2,500 random scenarios per year (brackets = tax, no negative values, tax rises with income), 1,664 extreme values, around 170,000 wealth and 113,000 lump-sum calculations across all municipalities and localities – 0 errors.
Tax at source: 1,245 checks: tariff files read without loss, official examples, samples per canton.
Property gains tax: 1,347 official examples and tables, 382 edge cases, 9,370 comparisons with the cantonal modules from the research, 1,108 co-ownership cases, 709 for ‘Advanced’ mode.
Inheritance & gift tax: 320 official cases (13 that cannot be modelled were skipped, with the reason) and 2,834 cases for the calculation core.
Pillar 3a, Pension or lump sum, Municipality ranking: 338, 97 and 176,950 checks of the calculation cores against the test values of the specification and independent individual calculations.

This measures agreement with the FTA calculator and with official examples, not with your tax assessment.

Test cases in detail (in German) ›

04Deliberate deviations from the FTA calculator

Where the law or official information differs from the FTA calculator, the Steuer-Zerleger follows the canton and flags this in the result, with the FTA calculator’s value alongside:

Personal tax: Ticino CHF 40 per person according to the law (FTA 20); Uri for Christian Catholics CHF 70 without church surcharge (FTA 100); Mümliswil (SO) 2026 Roman Catholic CHF 60 with the responsible parish (FTA 70).
Tax coefficients: officially documented errors in the FTA export have been corrected (2026: 15 municipalities), as have the 2026 wealth tax coefficients in Obergerlafingen, Solothurn, Feldbrunnen-St. Niklaus (SO) and Le Mouret (FR).
Lump-sum withdrawal tax: Schwyz 2026 according to the practice of the tax administration while the reduction of the maximum rate is pending before the Federal Supreme Court; exemption limits according to the law in Graubünden (CHF 6,200) and Fribourg (CHF 10,000); official conversion table for Ticino and Valais; Valais family reduction of at most CHF 2,450; rounding in Zurich as applied by the Cantonal Tax Office.

05What is not calculated

Fire service levies, property taxes and minimum taxes (except for the Valais cantonal tax of at least CHF 10).
Cantonal tax burden caps: only a note with the maximum amount by which they can reduce the tax, never in the total.
Allocation between several cantons, the municipality of work in Geneva and OASI/IV deductions on wealth (GL, SO).
Not yet all localities with their own tax coefficient; where known, there is a note next to the place.
Gross-salary estimator: travel costs and pillar 3a only via ‘Further deductions’, without the reduction for part-time work, the rent deduction (ZG) and the housing deduction (VD); children are assumed to be under 14.
Lump-sum withdrawal tax: residence abroad, benefits for surviving dependants and in the event of invalidity, a buy-in in the 3 years before the withdrawal, the repayment of a WEF early withdrawal. A staggered withdrawal calculates all years with the tax scale of the selected year.
Property gains tax: business assets, losses from other properties, communities of heirs.
Inheritance tax: business succession, usufruct and pensions, cases involving other countries.
Adopted reforms from 2027 onwards, for example in Vaud and Nidwalden, the change to the imputed rental value from 2029 and individual taxation from 1 January 2032.

06Changes

October 2026: wealth tax and personal tax; ‘Lump-sum withdrawal tax’ calculator.
29 October 2026: more precise marginal-rate steps.
31 October 2026: revised interface for both calculators.
1 November 2026: gross-salary estimator with the deductions of each canton; ‘Tax burden cap’ note.
2 November 2026: ‘Pillar 3a & buy-ins’ calculator.
4 November 2026: ‘Pension or lump sum?’ calculator.
7 November 2026: English, French and Italian; tax at source; ‘Property gains tax’ calculator with ‘Advanced’ mode.
8 November 2026: ‘Inheritance & gift tax’ calculator; lump-sum withdrawal tax in Fribourg, Valais and Zurich refined after a cross-check against the law and the cantonal calculator.
9 November 2026: Municipality ranking with a page for every canton.
10 November 2026: explanations, questions and example tables for every calculator, this methodology page, lump-sum withdrawal tax for every canton (in German).

07Who is behind it

The Steuer-Zerleger is a private, non-commercial project from Switzerland, with no advertising, no accounts and no cookies. Behind it is Fabian. It is not run on behalf of any bank, insurer or advisory firm, and there are no commissions or partners. What is counted, anonymously, is how often pages are viewed and features used, which website a visit comes from (only the domain, e.g. google.ch), which canton you are calculating for (only the abbreviation) and, when you switch year, the selected tax year – never amounts, municipality, religion or other personal details. Exactly what is counted is set out in the legal notice. The counter stores no IP address and passes nothing on to third parties; the web server’s access logs are used only for troubleshooting. Fonts and maps are hosted on the site’s own server; the site loads nothing from third-party servers. It is hosted by Hetzner in Germany.

08Contact

Found an error or have a question about the calculation? kontakt (at) steuer-zerleger.ch – ideally with the link from ‘Copy link’ (without amounts if you don’t want to share them). More about privacy can be found in the legal notice.