Despite many unmarried couples cohabiting, having children together, or sharing expenses, tax regulations establish a fundamental difference compared to married couples. This distinction means that, even if officially registered, each member of an unmarried couple must file their tax return individually.
“"For tax purposes, they are not considered a valid family unit for joint taxation. This implies that, even if officially registered, each member of the couple must file their declaration individually."
The Personal Income Tax (IRPF) regulations only recognize two types of family units for joint taxation: those formed by spouses and their children, and single-parent families with one parent and their children. Unmarried couples are excluded from both categories due to differences in legal regulation; marriage is governed by a single state law, while unmarried partnerships depend on various regional regulations.
Even with shared children, the declaration must be filed separately. However, it is possible to include children in a single-parent joint declaration, provided that only one parent includes them and the other files their individual return. This situation requires couples to annually assess the most beneficial option.
The Tax Agency and the courts have consistently upheld this criterion, arguing that marriage and unmarried partnerships are not legally equivalent figures. Therefore, those who choose not to marry also assume the fiscal implications of this decision.
Filing individual tax returns does not always result in an economic disadvantage. When both members of the couple have similar incomes, separate declarations can be more favorable by avoiding higher tax brackets. However, in cases where one member has very low income or is not working, or when it is not possible to offset losses and gains between both, separate filing can be detrimental.
