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IRS 2026: Filing Deadlines and How to Submit Your Modelo 3
Portugal's IRS calendar runs on fixed dates that repeat every year. Here's what's due when, and what happens if you miss one.
- Modelo 3 filing window is fixed every year: 1 April – 30 June.
- Two earlier deadlines feed your return: confirm your household by 15 February, validate e-Fatura invoices by 25 February.
- Late filing or payment carries 4% compensatory interest plus an RGIT fine, minimum €25.
- This page deliberately skips specific tax brackets — those change yearly via the State Budget; use Finkavo's calculators instead.
IRS (Imposto sobre o Rendimento das Pessoas Singulares) is Portugal's personal income tax, filed annually via Modelo 3 on the Portal das Finanças. The submission window itself is fixed by law — 1 April to 30 June — but several smaller deadlines earlier in the year affect what your final return looks like.
The IRS calendar, start to finish
| Date | What's due |
|---|---|
| 31 January | Choose your preferred language for AT services; landlords 65+ can request an exemption from electronic rent receipts |
| 15 February | Confirm your household (agregado familiar) and your registered fiscal address for the year |
| 25 February | Validate or dispute invoices logged in e-Fatura — this is what feeds your deduction totals |
| 15 March | Check the AT's calculated deductible expenses (you can appeal until 31 March if something looks wrong) |
| 1 April – 30 June | Submit your Modelo 3 |
| 31 July | Pay any IRS still owed after your assessment (segunda liquidação) |
Why the earlier deadlines matter
Everything before April feeds into your actual return. If your household composition is wrong on 15 February, or an invoice is missing from e-Fatura by 25 February, your pre-filled Modelo 3 and deduction totals will be wrong too — and it's much easier to fix upstream than to correct after filing.
How to submit
File through the Portal das Finanças — log in with your NIF and AT password, Cartão de Cidadão, or Chave Móvel Digital, then use the pre-filled Modelo 3 as your starting point rather than building it from scratch. Review every field before submitting; the pre-fill reflects what third parties (employers, banks, e-Fatura) reported, not necessarily your complete picture.
If you're self-employed (Categoria B)
You have extra obligations layered on top of the standard calendar: quarterly VAT declarations (20th of the month following each quarter), quarterly Social Security declarations, and — depending on prior-year income — payments on account (pagamentos por conta) due at fixed points across the year.
Rates and brackets: check the current year, not this page
IRS brackets, deduction ceilings, and special-regime caps (IRS Jovem, NHR, IFICI) are set or adjusted every year, usually in the State Budget (Orçamento do Estado) enacted around year-end. Rather than quote figures here that go stale within months, use Finkavo's calculators or the AT's own pre-filled return for the numbers that apply to your specific year.
What happens if you're late
A deadline that falls on a weekend or public holiday moves to the next business day automatically. Beyond that, late payment carries compensatory interest of 4% plus a fine under the RGIT (infractions code) — a minimum of €25 for an individual's IRS.
Frequently asked questions
What's the actual filing window for Modelo 3?
1 April to 30 June, every year — this date range itself doesn't change annually, though the specific bracket and deduction figures inside your return do.
Do I need to do anything before April?
Yes — confirm your household by 15 February and validate your e-Fatura invoices by 25 February. Both feed directly into your pre-filled Modelo 3.
What if I miss the 30 June deadline?
Late filing and late payment both carry consequences — compensatory interest (4%) plus a fine under the RGIT, minimum €25 for an individual. File as soon as you can rather than waiting.
Where do I find this year's exact tax brackets?
Not here — bracket and deduction figures change yearly via the State Budget. Use Finkavo's calculators or your AT pre-filled return for numbers specific to the current tax year.