The only canton with the sign reversed
In six of the seven cantons in our series the household pays too much because of the wrong tariff codes. In Thurgau it is the other way round — around CHF 126 a year too little is withheld.
That sounds like the pleasanter variant. It is not, and the reason is simple: whatever is underpaid during the year is missing later, when the final tax is calculated.
The use case
A married couple, both working, three shared children they can claim, salaries of CHF 174'000 and CHF 157'000. The husband's payslip shows B2 — married single earner with two children. The wife's shows C0: right letter, but no children. Both should have been C3.
Calculated with the official Thurgau 2026 tariffs without church tax, assuming twelve equal monthly salaries with no 13th salary and no bonus:
- Husband: 9.73 % instead of 12.41 % — around CHF 4'663 too little a year
- Wife: 14.26 % instead of 11.37 % — around CHF 4'537 too much a year
- Together: around CHF 126 too little
Why these CHF 126 say nothing about Thurgau
The net figure is so small that it flips as soon as you move the salaries. Shift both down by CHF 10'000 and CHF 270 too little appears; shift them up and it becomes more than CHF 800. With a different number of children the picture changes entirely.
No statement about the canton can be derived from this figure. It describes a single salary combination, not a property of the Thurgau tariff.
What is meaningful are the two individual amounts: CHF 4'663 too little on one salary, CHF 4'537 too much on the other. More than CHF 9'000 runs wrong — and the household notices nothing.
Underpaying is not a gift
Because one spouse in this use case already earns more than CHF 120'000, the couple is assessed under the ordinary rules. The tax at source actually paid is credited against the final tax. If too little was prepaid, a balance falls due — at a moment you do not choose.
How the Thurgau tariff is built
Thurgau taxes from the first franc. There is no tax-free zone at the bottom of the tariff, unlike Geneva, Zug, Schwyz or Aargau, and no minimum franc amount either — the percentage stands on its own.
Upwards the scale runs in CHF 50 steps to CHF 25'001 a month and more coarsely above, until it reaches its ceiling of 27.20 % at CHF 150'001. That is a good deal further than Aargau, which flattens at CHF 95'001, and further than Zurich at CHF 100'001.
For this household the practical consequence is simple: both salaries sit in the rising part of the scale, so both the tariff letter and the number of children still change the rate. A wrong code here is never neutralised by a flat ceiling.
What these figures are — and what they are not
They concern the running tax-at-source deduction, not the final tax. Because one spouse in this use case already earns more than CHF 120'000, the couple is assessed under the ordinary rules anyway — and the tax at source actually paid is credited there. The wrong code affects the household's liquidity first.
How to check your payslip
The tariff code has three parts: tariff letter, number of children you can claim, church tax marker. Check all three against your actual situation — and on both payslips, not just the conspicuous one.
A correct code is a good first check but not a complete one: with several employments the rate-determining income can be wrong too. In Thurgau a wrong code can mean too little is being deducted, which feels like nothing at all until the assessment arrives. If you find something, report it to HR. For years already closed, a tax-at-source correction should generally be requested by 31 March of the following year. And what you will actually owe in the end only shows once both salaries are calculated together — see our tax advisory for Thurgau.
The series: the same error in other cantons
- Zurich — where children relieve the most
- Geneva — the most expensive tariff letter
- Zug — low rates, large relative deviation
- St. Gallen — both effects strong
- Aargau — the error nobody notices
- Schwyz — the flattest tariffs
- What one child is worth — seven cantons compared