Low rates hide errors
Zug is the cheapest of the cantons we calculated. For a married couple with salaries of CHF 174'000 and CHF 157'000 and three children they can claim, the correct tax-at-source deduction is 4.09 % of gross salary. In Geneva it would be 11.89 %.
That has an unpleasant side effect: because the amounts on the payslip are small anyway, a deviation barely registers. A few hundred francs more or less a month are easily explained by a bonus, a salary adjustment or a holiday payout.
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 Zug 2026 tariffs without church tax, assuming twelve equal monthly salaries with no 13th salary and no bonus:
- Husband: 2.39 % instead of 4.55 % — around CHF 3'758 too little a year
- Wife: 7.07 % instead of 3.58 % — around CHF 5'479 too much a year
- Together: around CHF 1'721 too much
In relative terms the deviation is large
The absolute figure looks manageable. Put it in proportion and the picture changes: the wife is charged almost double the correct rate — 7.07 % instead of 3.58 %. In a high-tax canton a doubling like that would have been noticed immediately. In Zug it stays below the perception threshold because the starting amounts are small.
The gap between the single-earner and dual-earner tariff is 3.27 percentage points in Zug — on a base level of around 4 %. Measured against what is actually owed, that is one of the larger steps.
How the Zug tariff is built
Zug leaves the first CHF 2'601 of monthly salary untaxed and then keeps CHF 50 steps going the whole way up — nearly 4'000 separate bands, the finest gradation of the cantons we calculated. A salary change of a few hundred francs moves you a couple of bands, not a whole bracket.
The other end is what makes Zug unusual: the tariff is capped at 20.00 %. No matter how high the salary goes, the rate stops there. Zurich runs to 30.78 %, Geneva to 40.49 %.
Both facts point the same way. The percentages involved are small, so a wrong code produces a small franc amount per month — which is exactly why nobody notices it, and why it can sit on a payslip for years.
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 Zug the amounts are small enough that the net salary will look plausible either way, so the code has to be read rather than estimated. 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 Zug.
The series: the same error in other cantons
- Zurich — where children relieve the most
- Geneva — the most expensive tariff letter
- St. Gallen — both effects strong
- Aargau — the error nobody notices
- Thurgau — when the household pays too little
- Schwyz — the flattest tariffs
- What one child is worth — seven cantons compared