Instead of the tax class combinations III/V or in addition to the tax class combination IV/IV, employee spouses/life partners can choose the factor procedure.
By the tax class combination IV/IV in connection with the factor to be calculated by the tax office and to be formed as ELStAM, it is achieved that for each spouse/life partner by application of the tax class IV the basic allowance applicable to him is taken into account in the wage tax deduction and the wage tax deduction to be withheld by application of the factor of 0,... (always less than one) is reduced in accordance with the effect of the splitting procedure.
The factor is a tax-reducing multiplier which is calculated from the effect of the splitting procedure in the assessment if the spouses'/life partners' wages differ.
Example:
The expected wages of spouses/life partners A and B are 30,000 euros (A) and 12,000 euros (B). The wage tax for tax class IV is 3,951 Euros for A and 77 Euros for B. The total of income tax IV/IV is 4,028 Euro. The income tax for the joint earned income is 3,586 euros (splitting procedure).
This results in the factor of (3,586 euros : 4,028 euros =) 0.890. A's employer applies tax class IV plus factor to the wages of 30,000 euros: 3,951 euros x 0.890 = 3,516 euros. B's employer applies tax class IV plus factor to the wage of 12,000 Euro: 77 Euro x 0.890 = 68 Euro. The sum of the wage tax according to the factor method for the spouses/partners amounts to 3,584 euros and corresponds to the income tax to be determined for the entire earned income.
The wage tax for tax class III for A amounts to 1,360 euros and for tax class V for B 1,244 euros (sum of wage tax III/V: 2,604 euros). This leads to an additional payment of 982 Euros in the income tax assessment; the tax office can set advance income tax payments. This effect is avoided if the factor method is chosen, provided there is no other income.
Since 1.1.2018, both spouses are automatically classified in tax classes IV/IV when they marry. The same applies to same-sex married couples (§ 38b para. 1 nos. 3 and 4 and § 39e para. 3 sentence 3 EStG). Combination III/V is only awarded on application by both spouses. The combination IV/IV can therefore also be assigned to both spouses if only one spouse receives wages.
The tax class combination III/V is only applied if and as long as both spouses want this. The change from tax class III or V to tax class IV is also possible at the request of only one spouse with the consequence that both spouses are placed in tax class IV.
As with the choice of tax class combination III/V, the employee spouses/life partners are also obligated to submit an income tax return to the tax office when choosing the factor method.
.