This simulation shows how a removal of the so-called 'Ehegattensplitting' (joint tax filing) in German income tax law would affect couples. The system currently benefits couples with unequal incomes by treating their total income as a single pool that is split equally for tax calculations. In the following charts, we compare the current tax burden (with splitting) against a hypothetical individual taxation (without splitting) across various income levels and proportions.
This calculator shows your monthly net through tax classes, an approximation of the actual tax burden under the splitting tariff, a fictitious real-splitting compromise, and the scenario without splitting at the same time.
Why this matters: what you see month by month is not the same as what you actually pay.
The calculator shows four views side by side: class III/V for monthly perception, class IV/IV with factor as an approximation of the splitting tariff, fictitious real splitting as a reform compromise, and class I/I as the no-splitting reference.
Method: first we run class III/V as the monthly payroll view. The factor is calculated from a separate IV/IV baseline run without factor and is not derived from III/V, which avoids distortions from the withholding distribution. For fictitious real splitting we use the new simulation mode 3 with IV/IV as the neutral input: a capped transfer up to the basic allowance is applied to taxable income, after which both partners are taxed individually. For the no-splitting counterfactual we sum two separate class-I single calculations.
The lines below show the annual comparison against I/I as the zero line: green for the current splitting advantage, amber for fictitious real splitting as the compromise in between. Above that, the calculator separates monthly III/V perception from the cleaner IV/IV-with-factor tax view.
Calculating simulations...
Simulation of income tax per year for different income situations, Calculation engine used: www.obolusfinanz.de/en/taxapp
> With Splitting: Relieves unequal incomes, weakens work incentives
> Without Splitting: Strengthens work incentives, burdens classic single-earner models
Formally no. Splitting determines the annual tax in the assessment, while tax classes only shape monthly withholding. In practice they are linked because tax classes determine how strongly splitting is felt in day-to-day cash flow.
Because people react to monthly net income, not to the tax return. III/V makes visible how splitting changes ongoing cash flow and therefore labor incentives, especially for second earners.
The factor method distributes the expected annual tax more evenly across both partners. It is therefore a strong approximation of the splitting-tariff burden and avoids distortions in withholding.
Four perspectives at once: III/V as monthly perception, IV/IV with factor as an approximation of the actual tax burden, fictitious real splitting as a compromise, and I/I as the no-splitting reference.
It is not current law but a reform simulation: a limited income transfer of roughly the basic allowance is modeled first, and both partners are then taxed individually.
No. The final tax only results from the annual income-tax assessment. IV/IV with factor is, however, usually a very good approximation and often sits close to the final equalization.
I/I stands here for individual taxation without splitting. That makes it easy to see the tax advantage created by splitting and how an alternative system would change the result.
No. Social contributions depend on each individual income and are not changed by joint tax splitting.