The Spanish contribution base for autónomos: what it is and how to choose it

What the contribution base is

The contribution base is the monthly amount everything is calculated from: the contribution you pay Social Security and, from the same figure, temporary sick pay, the cessation-of-activity benefit and the retirement pension. It is not your turnover, nor your profit, nor the money left at the end of the month. It is a figure you choose.

What changed in 2023, with Royal Decree-Law 13/2022, is how far that choice goes. An autónomo used to be able to contribute on the minimum base whatever they earned. Now your income decides a bracket, and inside that bracket there is a minimum and a maximum base: you can move between them, but not outside.

The 2026 brackets: the full table

Article 18.1 of Orden PJC/297/2026 publishes two tables. A reduced one, of three brackets, for anyone below the floor of the general table. And a general one, of twelve. All amounts are monthly.

Two details the table hides at first glance. First: brackets 2 and 3 of the general table share the same minimum base, 960.78 €, so going from 1,500 to 1,700 € of income costs nothing extra if you contribute on the minimum. Second: the reduced table ends at "under 1,166.70" and the general one starts at "1,166.70 or more". That exact figure falls in the general table, and the jump in minimum base between the two sides is 101.31 €.

How the income that picks your bracket is calculated

This is where most do-it-yourself calculations go wrong. Social Security does not use the net income from your tax return as it stands. Article 308.1.c) of the General Social Security Act sets two steps:

1. Add back the contributions already paid. Under the direct-assessment method, computable income is the net income "increased by the amount of the Social Security contributions" of the holder of the activity. Because those contributions are deductible for income tax, Social Security returns them to the calculation.
2. Deduct a percentage for generic expenses. "A deduction for generic expenses of 7 per cent" applies to the amount above. For company-owner autónomos and worker-shareholders of employee-owned companies, that is letters b) and e) of article 305.2, the deduction is 3 per cent. Collaborating family members under letter k) keep the 7 %: that rule names only letters b) and e).

An example with round numbers: 2,000 € of monthly net income for tax purposes and 300 € of contributions paid each month. Computable income is (2,000 + 300) × 0.93 = 2,139 €, which falls in bracket 6 of the general table. Without the adjustment, the 2,000 € would have pointed at bracket 5 and a minimum base 65 € lower.

The autónomo contribution calculator performs both steps for you and shows the computable income before applying the table.

How much an autónomo pays: from base to contribution

Five rates apply to the base you choose, adding up to 31.50% in 2026:

At those rates, the 2026 minimum contribution is 205.88 € a month (653.59 × 31.50%) and the maximum is 1,606.88 € (5,101.20 × 31.50%). Against 2025 the table does not move, but the MEI rises from 0.80% to 0.90% along the scale in transitional provision 43 of the Social Security Act, so the contribution grows by exactly one thousandth of the base: 0.65 € a month on the minimum base and 5.10 € on the maximum.

Should I contribute on the minimum base

It is what the large majority do, and on a thin margin it makes sense. But it is worth seeing both sides before treating it as settled.

For the minimum: the difference shows up every month, and the money that does not go to the contribution can go to a pension plan, to a cash buffer, or simply to living.

Against: the base is what the benefit is calculated from. Long sick leave, a cessation of activity or the retirement pension are all paid in proportion to what was contributed. An autónomo in bracket 6 who moves from the minimum base (1,274.51 €) to their bracket maximum (2,330.00 €) pays 332.48 € more a month, and in exchange raises the base behind those benefits by 83%. There is no universal answer: there is a calculation each person has to run against the career years they have left.

One nuance about age: the final years of contributions weigh heavily in the pension, so raising your base at 30 and raising it at 55 do not have the same effect.

Why what you pay today is provisional

The base you choose during the year is provisional, article 308.1.a) rule 6 says. The following year, once the tax authority reports your actual income, Social Security reconciles:

• If you contributed below the minimum base of the bracket that applied, you pay the difference.
• If you contributed above the maximum base of that bracket, it is refunded.
• If your base fell inside the correct range, there is nothing to adjust, even if your income changed bracket.

That last rule is what gives you room to manoeuvre: as long as the base you chose still falls between the minimum and the maximum of the real bracket, the reconciliation touches nothing. That is why adjusting the base during the year, as soon as you see your forecast drifting, beats waiting for the settlement.

This information is educational and does not constitute tax or employment advice. For a specific case, consult an adviser or Social Security directly.