If both spouses/life partners receive wages, they can choose between two tax class combinations and the factor method when deducting income tax. The reason for this is that spouses/partners are generally taxed jointly, but only their own wages can be taken as a basis for the wage tax deduction of an employee. Only when the wages of both spouses/partners are combined after the end of the year when filing an income tax return does the correct annual tax result. It is therefore unavoidable that too much or too little income tax is withheld during the course of the calendar year. However, with the right tax class combination or the factor method, you can come as close as possible to the annual result.
The tax class combination IV/IV (statutory rule) assumes that the spouses/life partners earn the same amount. The tax class combination III/V is designed in such a way that the sum of the tax deductions for both spouses is approximately equal to the joint annual tax if the spouse/life partner with tax class III earns 60% and the spouse/life partner with tax class V earns 40% of the joint earned income.
Finally, spouses/life partners can also choose the factor method. The tax class combination IV/IV in conjunction with a factor of 0,... (always less than 1) to be calculated by the tax office and formed as ELStAM achieves the following:
For each spouse/life partner, the basic allowance to which he or she is entitled is taken into account when deducting income tax; at the same time, the income tax to be withheld is reduced by means of the factor 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' wages differ. The factor procedure can be applied for two years.