An ato isolado is always subject to VAT, whatever the amount (the art. 53.º CIVA exemption does not apply). The 25% withholding applies only to services and is waived up to €15,000 of annual income. The sale of goods has no withholding. An ato isolado generates no Social Security.
| Value of the service or goods (base) | €1,000.00 |
| VAT (23%) | €230.00 |
| = Total to invoice | €1,230.00 |
| IRS taxable income (coef. 75%) | €750.00 |
| IRS withholding (waived up to €15,000) | €0.00 |
| Social Security (an ato isolado does not contribute) | €0.00 |
| = You keep (before IRS) | €1,000.00 |
The taxable income (value × coefficient) is added to your other income and taxed at the general IRS brackets, so the final tax depends on your total income, and it is not computed here. The withholding is an advance on that IRS, settled in the annual return.
Educational estimate, not tax advice. It assumes the simplified regime, mainland VAT rates and a client with organised accounting for the withholding. It does not compute the final IRS. Check your situation on the Portal das Finanças.
Ato Isolado Calculator (One-Off Invoice) by Calculadora Capital