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Calculadora Capital

Ato Isolado Calculator (One-Off Invoice)

Issuing a one-off invoice (ato isolado) without opening activity? You always charge VAT, and the value feeds your IRS under the simplified regime. Enter the value of the service or goods, choose the income type and the VAT rate, and this calculator estimates the VAT to remit to the State, the IRS taxable income, the withholding (when it applies) and what you keep.

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.

Total to invoice (with VAT)
€1,230.00
VAT to remit to the State
€230.00
IRS taxable income
€750.00
Social Security
€0.00

How the figures are reached

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.

Video: how to use the calculator

What an ato isolado is

An ato isolado is a single, occasional provision of a service or sale of goods by someone who does not have (and does not want to open) registered activity with the tax office. It must be a one-off: if the activity is foreseeable or repeats, it is no longer an isolated act and you must register an activity as a self-employed worker. There is also a €25,000 yearly ceiling; above it, opening an activity is mandatory.

VAT: always due, whatever the amount

This is the part that surprises most people: unlike someone with registered activity, an ato isolado does not benefit from the article 53 VAT exemption. You must always charge VAT on the invoice and remit it to the State, even for a small amount. On the mainland the standard rate is 23% (there is also the 13% intermediate and the 6% reduced rate, depending on the good or service). The VAT is not yours: you collect it from the client and hand it to the tax authority.

IRS: only part of the value is taxed (the coefficient)

Under the simplified regime, IRS does not fall on the whole value: a coefficient is applied that presumes your expenses. For the provision of services (the art. 151.º list) the coefficient is 0.75 (75% of the value is taxable); for the sale of goods it is 0.15 (only 15%). That taxable income is added to your other income for the year and taxed at the general IRS brackets. So the final tax depends on your total income and marginal rate. This calculator shows the taxable income, not the final IRS.

Withholding and Social Security

For services, the client (if they keep organised accounting) withholds 25% of the value as an advance on IRS, but withholding is waived up to €15,000 of annual income (article 101.º-B of the IRS Code, which follows the article 53 VAT threshold). The sale of goods has no withholding. The withholding is not an extra tax: it is settled in the annual IRS return. Social Security does not apply: an ato isolado does not create a contribution obligation, because you are not a self-employed worker.

Worked example

Take a €1,000 service as an ato isolado, at the standard VAT rate (23%). You invoice €1,000 + €230 of VAT = €1,230, and remit the €230 of VAT to the State. For IRS, the taxable income is €1,000 × 0.75 = €750, added to your other income. As €1,000 is below €15,000, there is no withholding, and Social Security is €0. If it were a sale of goods, the taxable income would be just €1,000 × 0.15 = €150.

Frequently asked questions

What taxes do you pay on an ato isolado?
Two: VAT and IRS. VAT (usually 23% on the mainland) is always due and remitted to the State, whatever the amount. IRS falls on the taxable income (75% of the value for services, 15% for the sale of goods), which is added to your other income for the year and taxed at the general brackets. An ato isolado pays no Social Security.
Does an ato isolado have to charge VAT?
Yes, always. The VAT exemption for small income (article 53 of the VAT Code, up to €15,000) does not apply to isolated acts. You must charge VAT on the invoice (usually 23% on the mainland) and remit it to the tax authority, even for a low amount, unless the service is exempt for another reason (article 9, such as certain medical or teaching acts).
Is there withholding on an ato isolado?
Only for the provision of services and only above €15,000 of annual income: in that case a client with organised accounting withholds 25% as an advance on IRS. Up to €15,000 withholding is waived (article 101.º-B of the IRS Code). The sale of goods has no withholding. The withholding is later settled in the annual IRS return.
Does an ato isolado pay Social Security?
No. Someone issuing an ato isolado is not a self-employed worker and has no obligation to contribute to Social Security on that income. So Social Security is €0 on an ato isolado, unlike the recibos verdes of someone with registered activity.
How many atos isolados can I issue per year?
An ato isolado must be occasional and not foreseeable: in practice, one per type of activity per year. If the activity repeats, it stops being "isolated" and you must open an activity. There is also a value limit: above €25,000 per year, opening an activity as a self-employed worker is mandatory.

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Sources

Author: Thorben Rasmus Idel · Reviewed by: Nahar Geva · Last reviewed: 2026-06-06