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Separate or Joint Taxation for Couples in Portugal: How Household Deductions Are Split
👫 The Default Rule: Separate Taxation
- Married couples and unmarried partners (união de facto) are taxed separately
- Each spouse declares their own income and is taxed on it
- The dependants and their income are part of both returns, as explained below
📝 The Option: Joint Taxation
Couples can choose joint taxation (tributação conjunta):
- Both incomes are added together, and the total is divided by two (the quociente conjugal) to determine the rate
- The result is multiplied by two
- The option is made every year, in the IRS return, and must be made by both spouses
Unmarried partners can only opt for joint taxation if they’ve been living together for more than two years, with the same tax address.
⚖️ When Is Joint Taxation Better?
- Very different incomes: if one spouse earns much more than the other (or nothing), splitting the income can move the higher earner into a lower bracket
- Similar incomes: separate taxation usually gives the same or a better result
The Portal das Finanças simulates both options — always compare before submitting.
🧮 The 50/50 Rule for Household Deductions
This is the part many couples miss. With separate taxation:
- Personal expenses (each spouse’s own health, education, general family expenses, etc.) are deducted by the spouse who incurred them, with their own limits
- Deductions for dependants (the fixed amount per child) are split 50% for each spouse
- Dependants’ expenses (children’s health, education, general expenses) are also split 50/50, regardless of who actually paid
- Common expenses of the couple (for example, expenses issued to both or for the family home) are generally split in half
So even if one spouse pays all the children’s school fees, each spouse deducts half in their separate return.
With joint taxation, all deductions are added together in a single return.
🏠 What About Rent and Mortgage Interest?
- Rent for the permanent home and mortgage interest (on older contracts) are deductible within limits; when the contract is in both names, the deduction is generally split between the spouses in separate taxation
- Check the invoices and contracts to make sure they’re issued to the right NIFs
🌍 Spouses with Different Tax Residence
If one spouse is a Portuguese resident and the other isn’t, joint taxation is generally not possible — the resident spouse files individually (with specific rules for the household).
💡 Practical Tips
- Simulate both options every year on the Portal das Finanças.
- Check the e-Fatura of each spouse and the dependants.
- De facto union? Confirm you meet the two-year rule and share the same tax address.
- Separate taxation: remember that dependants’ expenses are split in half, whoever paid them.
🚀 Final Considerations
Separate taxation is the default, but joint taxation can save money when incomes are very different. Either way, the household’s deductions for dependants and common expenses are shared — split 50/50 in separate returns.
📢 Expert Advice: Don’t choose separate or joint taxation out of habit. Run both simulations every year — the best option changes when incomes change.
Filing IRS as a couple in Portugal? Step Inside Portugal’s tax team can compare the options and prepare your returns — find out more about our tax services here. ✨
This article is for general information only and doesn’t constitute tax advice. It reflects the rules as of October 2026.
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