Self-Employed Contribution

Self-employed contribution by real income: how it's calculated and what to pay each month

June 29, 2026

If you’re self-employed in Spain, your Social Security contribution is one of the most significant fixed costs of your activity. What you might not fully understand is how it’s calculated: why it can change from one year to the next, what it has to do with your invoicing, and why an unexpected adjustment letter sometimes arrives.

The answer lies in the contribution system based on real income, which links your monthly contribution to what you actually earn as a self-employed worker — not a freely chosen base. Understanding how it works is the key to paying the right amount every month and avoiding surprises at the end of the year.

self-employed self-employed contribution real income Social Security net earnings

From 80 to 400 euros a month: how to prepare your finances for when the tarifa plana ends

May 26, 2026

When you registered as an autónomo (self-employed worker), the tarifa plana (the reduced flat-rate Social Security contribution for new freelancers) was probably the best news in the whole process. Eighty euros a month for your Social Security contribution. Nothing. A huge relief in the first few months, when income is still on its way and every euro counts.

The problem is what comes afterwards. Because the tarifa plana ends. And when it ends, it doesn’t go up a little: it multiplies by four or five all at once. And it coincides precisely with the moment when many autónomos start to have real income, so the blow gets mixed up with the first sizeable quarterly IVA (VAT) and IRPF (personal income tax) payments.

self-employed flat rate self-employed contribution cash flow planning

I've received the contribution adjustment letter: what do I do now

May 22, 2026

If you’re an autónomo (self-employed worker) and you’ve received a letter from the Tesorería General de la Seguridad Social (the Spanish Social Security treasury) with an amount you weren’t expecting, take a breath. You’re not alone and it’s not a fine. It’s the contribution adjustment (regularización de cuotas), a new process that affects all self-employed workers since the system of contribution by real income came into force.

This guide explains what that letter means, how the difference they’re claiming from you (or that they owe you) is calculated, and above all how to stop it catching you off guard again next year.

self-employed self-employed contribution adjustment Social Security contribution by real income