Legal framework of non-marital partnership in Portugal
Non-marital partnership is recognised when two people live together for more than two years under conditions like those of a married couple.
For Income Tax purposes, the law treats de non-marital partnership the same as married couples, provided certain requirements are met—namely having a shared tax residence during that period.
This means that when submitting Form 3, de non-marital partnership have the same options as married couples.
Joint taxation vs. separate taxation
- Joint taxation
- The couple submits a single Income Tax return;
- Income is combined and divided by two (income splitting mechanism);
- It may reduce the effective tax rate, particularly when there is a significant difference in income between partners.
👉 This option is generally more advantageous when:
- One partner earns significantly less;
- Only one partner has income.
- Separate taxation
- Each partner submits their own tax return;
- Dependants’ income is split equally (50% each);
- Tax deductions are also divided.
👉 This option may be more beneficial when:
- Both partners have similar income levels;
- There are significant individual deductible expenses;
- The household is already in higher tax brackets.
What is the best option?
The answer is simple, yet often overlooked:
👉 it depends on the specific case.
The Portuguese tax system itself encourages simulation of both scenarios because:
- Income splitting may reduce overall tax;
- But dividing deductions can sometimes reduce tax benefits.
According to various tax analyses, there is no universal rule — the same couple may benefit from different options in different years depending on:
- Changes in income;
- The birth of children;
- Health, education, or housing expenses;
- Applicable tax benefits (e.g. IRS Jovem).
Key factors to consider before choosing
Before submitting Form 3, you should review:
- ✔️ Income differences between partners
- ✔️ Number of dependants
- ✔️ Total tax deductions
- ✔️ Applicable tax benefits
- ✔️ Simulations on the Tax Authority portal (joint vs. separate)
⚠️ Important: the choice is made annually, meaning it can be adjusted each year to maximise tax efficiency.
Common mistakes to avoid
- Assuming that joint taxation is always more beneficial
- Failing to simulate both scenarios before submission
- Incorrectly declaring the household composition
- Ignoring the impact of deductions and tax benefits
Conclusion
Choosing between joint and separate taxation for Non-marital partnership in Portugal should not be based on intuition, but on concrete simulations and technical analysis.
In many cases, small differences in income or expenses can result in hundreds or even thousands of pounds (or euros) difference in the final tax bill.
👉 The right decision is simply the one that legally minimises your tax.
How Nominaurea can help
At Nominaurea, we analyse each tax situation in detail to ensure you choose the most advantageous option.
✔️ Professional tax simulations (joint vs. separate)
✔️ Household tax optimisation
✔️ Full support with Form 3 submission
✔️ Tax planning for future years
Avoid paying more tax than necessary — get in touch with us.
