Relevant income (quarter)–
Monthly base–
Contribution per month–
Over the 3 months–
This simulator uses the 21.4% rate for self-employed workers. Sole traders (empresários em nome individual) and EIRL holders pay 25.2%.
How it is calculated
Relevant income = 70% of services + 20% of sales of goods in the previous 3 months. The monthly base is one third of that (maximum 12 × IAS = €6,445.56 in 2026); if there is no income or the contribution is below €20, you pay €20 per month, and you can adjust it between −25% and +25%. The rate is 21.4%. The quarterly declaration is due by the end of January, April, July and October.
There are exemptions (for example, at the start of activity, until the 1st day of the 12th month, or when combined with employment under certain conditions) that this calculator does not check.
Approximate simulation, with no official value, and not tax advice. It uses the general 2026 rates and simplified rules: it does not take into account tax credits (deduções à coleta), the minimum subsistence amount (mínimo de existência), IRS Jovem, other household income, aggregation of income (englobamento), the increase in taxable income under art. 31 of the CIRS (unjustified expenses), or the IRS rates of the Autonomous Regions. The real result may be very different. Always check on the Portal das Finanças, on Segurança Social Direta or with a certified accountant (contabilista certificado). This site does not belong to and is not associated with the Autoridade Tributária e Aduaneira (AT) or the Segurança Social. Sources and rates.