Tool · IAB calculator
IAB calculator
Estimate online how an investment deduction (IAB) and, where applicable, a severance payment with the fifth rule (Fünftelregelung) affect your income tax, the solidarity surcharge and church tax — tariff 2025 and 2026 under § 32a EStG.
Simplified calculation for orientation only. Does not replace individual tax advice.
Inputs
Enter as a number: 190000 or 190.000 or 190.000,50 (German format)
In EUR. Negative values allowed (e.g. after high deductible expenses or loss carry-overs).
Extraordinary income within § 34 (2) EStG. Leave empty or 0 if none.
Up to 50 % of the projected acquisition cost, max. 200,000 € over three years (§ 7g EStG).
Optional — if entered, the additional depreciation volume from special and declining-balance depreciation is shown explicitly.
Result
The calculation is based on the tax tariffs under the EStG and SolZG; church tax is only applied when a federal state is selected (8% in Bavaria/Baden-Württemberg, otherwise 9%, without state-specific capping). No warranty as to accuracy — we reserve the right to errors in the calculation program. The calculation does not replace individual tax advice. Maximising the tax saving via IAB is not always the best overall solution; rather, a holistic tax planning across the entire investment horizon is required in each individual case. In some cases it can even be more favourable not to claim an IAB at all. Please obtain qualified advice for your specific case.
Methodology & legal notes
This calculator considers tariff income tax under § 32a EStG, the solidarity surcharge under § 4 SolzG (incl. the threshold under § 3 (3) SolzG: 20,350 € single tariff / 40,700 € splitting tariff) and — when a federal state is selected — church tax (8% in Bavaria and Baden-Württemberg, otherwise 9% of the income tax; without state-specific capping). Other types of income, loss offsetting, special expenses (including the special-expense deduction for church tax), extraordinary burdens, the progressive proviso (Progressionsvorbehalt) and other personal factors are not included.
The fifth rule (Fünftelregelung, § 34 EStG) is applied in the standard case and the special case of sentence 3 (current zvE negative). Assumption: the severance entered meets the conditions of extraordinary income (concentration of payment, agreement in line with BFH case law). These conditions must be verified individually.
Tariff 2026 reflects § 32a EStG in the version applicable for VZ 2026. Tariff 2025 accordingly for VZ 2025. The calculator will be updated when the tariff schedule changes.
The calculator does not replace tax advice for your specific case. For application to your individual situation a personal review is required. No liability is accepted for the accuracy of the calculation shown here.
Personal advice for your situation
The calculator gives an initial orientation. For the concrete structuring of your IAB, the verification of the prerequisites under § 7g EStG and the optimisation of your overall tax situation we are happy to assist you personally.
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