Joint or separate tax return in Portugal: which pays off
If you are married or in a civil partnership (união de facto) in Portugal, every year you choose between a joint or separate IRS return. The choice can be worth hundreds or thousands of euros. Here is how each option works, when joint filing pays off and worked numbers.
The two options
Since the 2015 IRS reform, separate filing is the default for married couples: each spouse declares their own income. Joint filing is an option ticked in the return (articles 13 and 59 of the IRS Code). Unmarried partners can also opt for it if they meet the legal requirements of a união de facto (living together for more than two years) and share a tax address.
| Joint | Separate | |
|---|---|---|
| Returns | One for both | One each |
| Rates | Taxable income split in two | Each on their own income |
| Shared children | Full deduction | 50% on each return |
| Household caps (health, education…) | Full | Half each |
Income splitting
With joint filing, the couple's taxable income is added up, divided by two, taxed using the tax brackets and multiplied by two (article 69). Because rates are progressive, this lowers the tax when incomes are very different; with equal incomes it makes no difference.
Worked example: €40,000 + €10,000
Rui earns €40,000 gross a year and Sofia €10,000, both employees, no children, €250 of general expenses each, 2026 rates including the approved cut.
- Separate: Rui's taxable income is €35,412.91, gross tax €8,000.91, minus €250 = €7,750.91. Sofia's income falls under the tax-free minimum, so she pays €0 and her €250 credit is wasted. Couple total: €7,750.91.
- Joint: taxable income €40,825.82; half is €20,412.91; tax 2 × that = €6,715.20, minus €500 = €6,215.20.
Joint filing saves €1,535.71 a year. The table below shows more couples (gross annual employment income, mainland, €250 of general expenses each, 2026 rates with the cut, total tax for the couple):
| Incomes | Children | Joint | Separate |
|---|---|---|---|
| €40,000 + €10,000 | 2 | €5,015.20 | €7,150.91 |
| €30,000 + €0 | 0 | €2,875.38 | €4,450.27 |
| €60,000 + €15,000 | 0 | €13,075.35 | €15,853.90 |
| €25,000 + €25,000 | 0 | €6,215.20 | €6,215.20 |
Look at the case with two children: filing separately, half of the €600-per-child credit goes on Sofia's return, where there is no tax to offset, so it is lost. Filing jointly, the full €1,200 comes off the couple's tax. With the 2026 Budget rates (without the cut, which still awaits publication) the gap for the first example is almost the same: €6,385.96 joint against €7,899.26 separate.
When each option wins
- Big income gap or one spouse without income: joint almost always wins.
- A low earner who pays no tax: on separate returns their share of child and other credits is lost.
- Similar incomes: practically the same result.
- Special cases (other income types, IFICI, tax debts, very uneven deductions): there is no general rule, so simulate both.
- IRS Jovem still applies to whoever qualifies under either option — see IRS Jovem.
Use the Simulate button on the Portal das Finanças for both options, compare the couple's total, and file on time (1 April–30 June): the joint option only counts if the return is filed within the legal deadline. You choose again every year. If you use IRS Automático, check the option before accepting.
Monthly withholding
Your filing choice does not change the monthly withholding table. Married couples where both work use table I; if only one works, table III, which withholds less. The real tax is settled on the annual return either way.
On fisco.pt, the annual IRS section of the salary calculator compares joint and separate filing automatically: say you are married and enter both incomes. For each spouse's monthly pay, see the net salary guide.
Common mistakes
- Comparing only one spouse's result instead of the couple's total.
- Forgetting to split shared children on separate returns.
- Filing late and losing the joint option.
- Assuming joint is always better.
FAQ
What is the default for married couples?
Separate filing. Joint must be chosen in the return.
Can unmarried partners file jointly?
Yes, if they meet the união de facto requirements and share a tax address.
Can we switch next year?
Yes, the choice is made every year.
Does it change monthly withholding?
No. Withholding depends on whether one or both of you work — see withholding tables. For deductions, see IRS deductions.
Run the numbers with your own figures
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