Key figures — as of 2026-08-31: IRS refunds due for returns filed on time (1 April–30 June 2026) had until 31 August 2026 to be paid — the legal deadline under the IRS Code — after which compensatory interest of 4% a year starts accruing daily from 1 September; that works out to roughly €0.11 per day for every €1,000 still owed; taxpayers generally must file a reclamação through Finanças' e-Balcão to actually get the interest paid.
The deadline just passed — now what
If your IRS refund hadn't landed by yesterday, you're not just waiting anymore — you're owed money for the wait. By law, the IRS refund must be issued by 31 August of each year, provided the tax return was also filed within the legal deadline — 1 April to 30 June 2026 for income earned in 2025. Miss that date, and compensatory interest becomes due, counted day by day from the end of the refund deadline until the credit note is issued.
This matters disproportionately for foreigners. Non-resident filers, people with income from multiple countries, freelancers on recibos verdes, and anyone whose declaration triggers a manual review at Finanças are exactly the profiles most likely to see their refund slip past August — precisely the cases where the interest clock is most likely to start running.
How much is 4% actually worth
The rate applied to these compensatory interest payments matches the legal interest rate set out in Article 559 of the Civil Code, currently fixed at 4% a year. In plain terms, for every €1,000 of delayed refund, 4% a year works out to €40 annually, or about €0.11 a day, counted from the day after the deadline expires.
That sounds like pocket change, and for most people it is. But GrowIN's own calculation shows where it starts to add up: a foreign remote worker or freelancer owed a €3,500 refund — not unusual for someone who overpaid withholding tax while adjusting to Portuguese payroll rules mid-year — who waits 90 days past 31 August would accrue roughly €34.50 in interest alone, on top of the refund itself. For a household with two filers each owed similar amounts, that's closer to €70 in interest for a delay most people wouldn't even think to query.
The catch: you have to ask for it
Here's the part that catches foreign taxpayers out. Compensatory interest represents compensation for the waiting time and the financial impact of the delay, and it should be claimed whenever it isn't automatically included. In practice, Finanças doesn't reliably add the interest to a late refund on its own. If payment was made after 31 August and didn't include any additional interest amount, there are grounds to file a formal complaint.
The process itself is straightforward but easy to miss if you're not fluent in the Finanças portal's menus. It's done through the Portal das Finanças, in the e-Balcão section, selecting IRS and then Reclamações e Recursos, or the request can also be made in person at a Finanças office. In the claim, you should state that the refund was processed outside the legal deadline and expressly request payment of the compensatory interest you're entitled to by law.
Once submitted, don't expect instant resolution. The tax authority has 120 days to respond to the complaint; if the response is favourable the interest gets paid, and if the AT doesn't recognise the right to interest or doesn't reply in time, the taxpayer can escalate to the Tax and Administrative Court, ideally with specialist legal support.
What this means in practice
GrowIN Portugal Editorial says: the interest itself is rarely life-changing, but the principle is — Finanças is legally on the hook for its own delays, and it won't chase you down to pay up.
For foreigners still navigating the Portal das Finanças, IBAN registration and the quirks of Portuguese tax residency, this is a useful reminder that the system has built-in accountability mechanisms — you just have to trigger them. Anyone still waiting on a refund should log into the portal, confirm the liquidation date on their tax assessment, check whether interest was already folded into the payment, and file the claim if it wasn't. It costs nothing and takes minutes.
Our tax and NIF guide covers the wider IRS filing calendar, withholding rules and what to do if Finanças flags a discrepancy in your return — worth a look if this is your first refund season in Portugal.
Whatever the sum involved, the rule stands: Finanças owes interest on late refunds, but only pays it to those who ask.