Two colleagues with the same salary and the same bonus, and yet one gets noticeably more paid out. The reason is almost always the tax class (Steuerklasse). It determines how much income tax the employer withholds. What tax is really due, however, is only settled by the tax return. As of October 2026.
How much the income tax varies
Example: 3,500 € gross a month, 1,000 € bonus, no children, no church tax. Social contributions are the same in every tax class (217.50 €):
| Tax class | Income tax on 1,000 € | Net |
|---|---|---|
| III | 170.00 € | 612.50 € |
| I / IV | 232.00 € | 550.50 € |
| V | 322.00 € | 460.50 € |
With a smaller salary the gap is even larger. With 2,500 € gross a month, the income tax on a 1,000 € bonus in tax class III is zero and you get 782.50 € net. In tax class V it is only 447.50 €.
Why is that?
The income tax on the bonus is the difference between two annual tax amounts, with and without the bonus (§ 39b (3) EStG). What matters is the rate that applies to the additional euro.
- Tax class III uses the splitting tariff. Income is halved, the tax doubled. Your marginal rate is therefore low.
- Tax class V is the counterpart to III. The basic allowance and standard allowances are largely missing, so the marginal rate is high even for small salaries.
- Tax class VI for a second job has no allowances at all.
Is it worth switching tax class before the bonus?
Married couples and registered partners can change tax class several times a year. An application to the tax office for the current year is possible until 30 November (§ 39 (6) EStG). The change takes effect from the following month.
For the bonus this achieves nothing that would not happen anyway. The tax class only governs the advance the employer withholds. Couples are assessed jointly, and their joint income is what counts. If you paid too much in class V, you get it back with the tax return; if you paid too little in class III, you pay the difference. With the III/V combination you are obliged to file a tax return (§ 46 (2) No. 3a EStG).
Careful with wage replacement benefits: parental allowance, unemployment benefit and sickness benefit are based on net pay and thus on the tax class. A switch can have a big effect here, positive or negative. That is a better reason to choose a tax class than the Christmas bonus.
The factor method as an alternative
Instead of III/V, couples can choose the factor method with IV/IV. The factor distributes the joint tax according to the ratio of incomes. Withholding is then closer to the actual annual tax, and back payments become rarer.
Getting overpaid tax back
A tax return is especially worthwhile after a year with a bonus if
- you worked in tax class V or VI,
- your work expenses exceed 1,230 €, for example because of a long commute,
- you were not employed all year,
- a full 5.5 % solidarity surcharge was withheld on the bonus although your annual income is in the phase-in zone.
The tax refund calculator estimates what you may get back. The tax class calculator shows which combination suits a couple.
Your bonus in every tax class
Below the result, the Christmas bonus calculator shows a table with your net bonus in all six tax classes.
Sources: § 39b (3) EStG, § 39 (6) EStG, § 46 (2) EStG (gesetze-im-internet.de), official wage tax flowchart 2026. As of October 2026.