tax-class-comparison germany

Explanation & FAQ (short, but helpful)

Tax classes do not determine "how much tax you really pay", but mainly how much wage tax your employer withholds month by month. The final income tax is only determined with the tax return (or the annual wage tax adjustment) based on your total taxable income. This is exactly why a change of tax class can significantly shift the monthly net income – without changing your core annual tax liability. This tool is therefore a change comparison: It shows how two scenarios affect your current household net income and the rough "refund/back payment feeling".

For married couples, three variants are usually interesting: IV/IV, III/V, and IV/IV with Factor. IV/IV is often "neutral" if both earn similarly. III/V shifts more net income to the partner with Class III and less net income to the partner with Class V. This can help in everyday life (e.g., if one income covers the fixed costs), but carries higher risks of back payments – especially with fluctuating incomes, special payments (bonus/Christmas bonus), or if the work situation changes during the year. IV/IV with Factor attempts to smooth this out: Both pay proportionally so that the sum of the wage tax is closer to the expected joint annual tax.

How to use the comparison: Enter your gross salaries (monthly), select church tax (0/8/9 %), and adjust the additional contribution to statutory health insurance if you know the specific fund value. Optionally, you can specify the number of children (for deductions in nursing care insurance) and activate "childless over 23" (care insurance surcharge). Then select Scenario A and Scenario B and click on "Calculate". The result tiles show net income per person, joint household net income, tax deductions, and the difference between A and B.

How does the tool calculate? It first estimates social security contributions (pension, unemployment, health, and nursing care insurance) with typical employee shares and takes into account contribution assessment limits. Subsequently, a simplified taxable income is determined (gross minus social security contributions minus lump sums like the employee allowance and special expenses allowance). Income tax is estimated on this basis using the 2026 income tax tariff according to § 32a EStG; for married couples, the splitting method is modeled for the annual tax.

Interpretation: If Scenario B shows more net income, this does not automatically mean "better". Ask yourself additionally: Does the monthly distribution fit your everyday life? And how likely is a refund or back payment? III/V can "optimize" the monthly net income, but is more sensitive if something changes during the year. The factor is often the less stressful variant because it reduces surprises. As a rule of thumb: The more unequal the incomes, the more III/V shifts net income to the main earner; the more similar the incomes, the closer IV/IV lies – and the factor often brings the cleanest planning.

Tip: Use the calculator also as a "Stress Test". Calculate once conservatively (without bonus) and once optimistically (with bonus/13th salary as a surcharge on the monthly gross). If the difference between the scenarios is small, a switch is often only worthwhile if you become more plannable (e.g., Factor instead of III/V) or if a benefit (parental allowance/sick pay) is to be specifically influenced via the net income.

FAQ
1) Does the tax class change my annual tax? Usually not. It mainly changes the monthly prepayments (wage tax). The actual annual tax depends on total income and deductions.
2) When is III/V worthwhile? Often with very different incomes, if you consciously want more net income for the main earner. Plan for reserves in case a back payment arises.
3) Why IV/IV with Factor? Because the wage tax for both partners is adjusted proportionally. This makes the household net income more plannable.
4) Do I have to file a tax return? With III/V, the obligation to file is present in many cases. Check current rules or clarify briefly with the tax office.
5) Can I switch at any time? Basically yes, but deadlines and limits apply (e.g., how often per year). Practically, this is done via ELSTER or the tax office.
6) How accurate is the calculator? It is an approximate comparison with standard values. For exact figures, ELStAM data and the payroll are decisive.
7) What about Bonus/Christmas money? Special payments often increase deductions significantly in that month. If relevant: test several variants.
8) Does the tax class affect Parental Allowance/Sick Pay? Indirectly yes, because benefits are often oriented towards net income. The timing of a switch can therefore be decisive.
9) Why does the annual tax often remain the same? Because the income tax tariff and splitting determine the annual burden. Tax classes primarily shift only the time of payment.