IRS 2026: March 16-31 Is Your Last Chance to Check Tax Deductions—Here's What Expats Need to Know

If you filed Portuguese taxes last year, the clock is ticking. Between March 16 and 31, 2026, you must review your e-Fatura deductions for 2025 income—or risk losing money. This is the official window to verify health, education, housing, and elderly care expenses that reduce your tax bill.

Miss it, and you forfeit the right to claim missing receipts. For expats unfamiliar with Portugal's tax calendar, this deadline often flies under the radar. Here's what you need to do—and why it matters.

What Is the March 16-31 e-Fatura Review Period?

Portugal's tax system relies on e-Fatura, an automated receipt-tracking platform where businesses upload invoices tied to your NIF (tax ID number). The Autoridade Tributária (Tax Authority) aggregates these receipts and calculates deductions for your IRS (income tax) return.

But the system isn't perfect. Receipts get miscategorized. Doctors' visits end up under "general expenses" instead of "health." Rent payments don't register as housing deductions. Pharmacy purchases slip through the cracks.

Between March 16 and 31, you have the legal right to review and correct these errors. After March 31, you're stuck with whatever the system calculated—even if it's wrong.

What You Should Check Right Now

Log into faturas.portaldasfinancas.gov.pt using your NIF and Portal das Finanças password (or Chave Móvel Digital). You'll need to check four main categories:

1. Health Expenses (Saúde)

Doctor visits, dentists, physiotherapy, prescriptions, eyeglasses. These qualify for deductions, but only if properly categorized. Private health insurance premiums also count.

2. Education Expenses (Educação)

School tuition, textbooks, extracurricular activities for dependents. If you have children in Portuguese schools—or sent them to schools in Portugal's interior regions or autonomous regions—check this section carefully. Interior schools trigger additional deductions.

3. Housing Expenses (Habitação)

Rent payments and mortgage interest. If you're a tenant, ensure your landlord uploaded rental receipts. If you own, verify mortgage interest appears correctly.

4. Elderly Care (Lares de Idosos)

Nursing home or assisted living costs for elderly family members. This is a high-value deduction often overlooked.

How to Fix Errors

If you spot a missing or miscategorized receipt, you can file a complaint (reclamação) directly through the e-Fatura portal. The deadline is March 31. After that, the Tax Authority locks in the numbers.

For each member of your household—including children—you must validate receipts individually. The system doesn't auto-populate dependent expenses. You need to log in under each NIF and approve receipts manually.

Other Key IRS Deadlines This Year

March 31: Last day to designate an IRS consignment (donate 1% of your tax to a cultural, youth, or sports organization). Also the final day to correct e-Fatura deductions.

April 1 – June 30: IRS filing period. You submit your 2025 tax return online. Most expats with simple income (salary, pension) can use the automatic IRS option—the Tax Authority pre-fills your return based on employer/pension data. You just review and approve.

By August 31: If you're owed a refund, the Tax Authority has until the end of August to pay you. Delays happen if your return has errors or triggers audit flags.

What This Means for Expats

For first-time filers: This is your introduction to Portugal's tax admin burden. The e-Fatura system is more automated than most countries, but it requires active monitoring. Set calendar reminders for March 16-31 every year.

For NHR holders: Even if your foreign income is exempt under the Non-Habitual Resident regime, you still file Portuguese taxes. Portuguese-source income (local salary, rental income from Portuguese property) follows standard deduction rules. Don't assume NHR means no IRS obligations.

For retirees: Pension income from abroad may be tax-exempt under NHR, but Portuguese pensions are fully taxable. Health expenses become critical deductions as medical costs rise with age. Review receipts carefully.

For families: Education deductions add up fast if you have kids in private or international schools. Interior school bonuses apply if you moved to rural Portugal for cheaper housing—an increasingly common expat pattern.

For landlords: If you rent out property in Portugal, you should have filed Modelo 44 by March 2, declaring rental income. Housing expense deductions on your own rent or mortgage are separate—check them in e-Fatura by March 31.

Common Expat Mistakes

Not checking dependents' receipts: Your child's dental visit won't automatically count. You must log into their NIF and validate it.

Assuming the system is perfect: It's not. Pharmacies routinely misfile prescriptions. Landlords forget to upload rent. Double-check everything.

Missing the March 31 deadline: There's no grace period. After March 31, you file your return with whatever e-Fatura calculated, correct or not.

Forgetting the automatic IRS deadline: If you qualify for automatic filing (most salaried workers and pensioners do), you can approve your pre-filled return as early as April 1. Approving early doesn't mean you get refunds faster—payouts still happen by August 31—but it clears the administrative burden.

The Bigger Picture

Portugal's tax system is digitized and relatively transparent compared to peers, but it demands engagement. The e-Fatura review period is non-negotiable if you want to maximize deductions. For expats juggling multiple countries' tax obligations, this is one more compliance task—but it's worth the effort. A few hundred euros in recovered deductions can cover a month's groceries or a weekend trip.

If this is your first year filing Portuguese taxes, consider hiring a contabilista (accountant) to walk you through it. First-time filers often leave money on the table simply because they don't know what to check. After one guided cycle, most expats handle it themselves.

But whether you DIY or hire help, don't skip the March 16-31 window. It's the difference between getting back what you're owed and paying more than you should.