Autonomos in Spain are required to pay a monthly contribution into the state social security system.
In return, they earn access to the state healthcare system, a claim to modest sick pay, eventually a modest pension, and invalidity benefits .
How much you have to pay is guided by your yearly earnings. Your earnings fall into a specific bracket that has a minimum and maximum. See the Social Security brackets for 2026.
You can voluntarily choose to pay in more up to the maximum amount to increase what you get back.
This calculator helps you find out how high you should set your monthly contribution and what you can expect in return.
Seguridad Social have no way to see how much you're currently earning. Therefore, the amount that you pay every month is based on your estimate of how much you will earn this year, and should be treated as a pre-payment rather than a fixed amount.
Once Seguridad Social know how much you have earned from your yearly income tax return, a process called regularización starts: how much you paid and how much you really owe is calculated, and you may receive an additional bill, or receive money back.
This process typically happens in the year after you have handed in your tax return. For example, the tax return for 2025 was due in June 2026, and we can expect the regularización some time in early 2027.
To estimate your regularización, we have a specific tool: the Social Security Regularización Calculator.
There are social security calculators out there, but I don't think there's one that is quite detailed. You can adjust contributions and see what you would really be getting, as well as an estimate of your pension, even though I imagine the rules around that might change before most of you enter pension age. Give it a try and let me know how it works for you!