Turn extra income into clean money — without tax surprises

In 5 min you'll know: how to register your freelance activity and pre-calculate tax before spending the first euro

In Block 1, Lesson 1, you learnt to read your payslip and identified your NIF (Portuguese tax-ID number) and your NISS (Portuguese social-security number). Now you'll need those two numbers more than ever — because if you start earning money on your own, you become your own employer and the State wants its share. The rule: register your activity and calculate the tax before you spend the first euro of extra income.

Before you continue: reading your payslip, do you know how much is withheld for IRS (Portugal's personal income tax) each month — and what happens if the withholding is wrong?

(Answer in the next paragraph.)

Let's start with extra income. You give private tuition, do freelance work, sell items online, provide occasional services. If you receive money for it, it's income. And income in Portugal is taxed — even if it's occasional. The self-employed regime (recibos verdes) requires you to issue a receipt for each service provided, pay social-security contributions and file an IRS return. There's no shortcut: if you earn, you declare.

The acto isolado (isolated act) is the exception for those without a registered activity. If you did a one-off job and aren't self-employed, you can declare that income as an acto isolado on your IRS return. But the AT (Autoridade Tributária) already monitors patterns — if you declare isolated acts every year, they'll question whether you should have a registered activity. The practical rule: more than 2-3 isolated acts per year? Register your activity. It's simpler, cleaner and avoids problems.

VAT is the surprise nobody explains to you. If you register your activity and your annual turnover exceeds €14,500 (exemption threshold in 2025), you must charge and remit VAT. Even below that limit, there are sectors where VAT is mandatory regardless of volume. And if you charge VAT but don't remit it to the State on time, fines start at €200. The periodic return schedule (monthly or quarterly) depends on your billing volume. Yet another reason to have your tax calendar set up.

Social security for self-employed workers is calculated based on the average income from the last 3 months. If you're in the self-employed regime (Decreto-Lei n.º 43/2018), the rate is 21.4% on relevant earnings. But there's a minimum and a maximum. And in the first 12 months of starting your activity, you may qualify for a partial exemption. Find out before — not after — you open the door to your first client.

Register your activity and pre-calculate tax (3 min) →

Your promise: This fortnight, Monday at 7pm, I will register the freelance activity and calculate estimated tax before spending.