In the case of joint tax assessment, both spouses submit a joint tax return. The income of both spouses is first added up and then halved. Income tax is calculated for half of the taxable income, which is then doubled. This taxation procedure, also known as spouse splitting, is particularly beneficial for couples with large income disparities, as it results in a lower average tax rate.
If, on the other hand, the income of both spouses is approximately the same, the aggregation of income and the application of the splitting tariff does not have any advantage over the separate taxation of the spouses.
A precondition for joint tax assessment is that the spouses are married to each other and have unlimited tax liability and live together on at least one day of the year.
If you do not select any form of assessment on the tax return's cover sheet, the tax official will automatically carry out a joint assessment.