Self-employed contribution adjustment calculator 2026

Don't let the adjustment catch you off guard

If you track your income and expenses in Cuéntamo, your net income is calculated automatically as the year goes on: you know which bracket you'll fall into before the adjustment and can adjust your base in time, instead of getting a nasty surprise. The Forecast warns you of the hit in advance.

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What the adjustment is and why it exists

Since 2023, self-employed workers in Spain contribute to Social Security based on their real net income, rather than on the base each person used to choose freely as before. The catch is that your real income isn't known until the year ends and you file your income tax return. That's why the system works in two stages: during the year you contribute on a provisional base, and the following year it's adjusted.

How it works, step by step

You choose a contribution base within the bracket you estimate based on your expected income.
You pay your monthly contribution on that base.
Once the year ends, the Tax Agency reports your real income to Social Security.
Social Security compares the base you contributed on with the bracket you were due and adjusts: it refunds any overpayment or bills you for any underpayment.

How your bracket is worked out. Your annual net income is divided by the number of months registered to get an average monthly income. That figure places you in one of the 15 brackets of the 2026 table, each with a minimum base and a maximum base. If you contributed below your bracket's minimum base, you pay the difference; if you contributed above the maximum, you get it refunded; if your base was within the range, there's no adjustment.

When it arrives

With a delay. A given year's adjustment is done during the following year, once the income tax filing season is over. Refunds are automatic —you don't have to request them— and must be completed before 30 April of the year after the income was reported. If you have to pay in, you'll get a deadline to settle the difference (with the option to spread payment), with no surcharge if you do it within the deadline.

How to avoid surprises

The key is to adjust your base during the year. You can change it up to six times, effective in March, May, July, September, November and January. If you see your income rising, raise your base in time and you'll avoid being billed a big difference all at once. And if it falls, adjust it so you don't overpay.

Frequently asked questions

Since 2023, self-employed workers in Spain contribute based on their real net income. During the year you contribute on an estimated base; the following year, when the Tax Agency reports your real income to Social Security, it adjusts what you paid: if you overpaid, you get a refund; if you underpaid, it bills you the difference.

A given year's adjustment is done the following year, after the income tax filing season. For example, the 2024 contributions are adjusted during 2025-2026. Automatic refunds must be completed before 30 April of the year after the income was reported.

Because you contributed on a base lower than the one you were due according to your real income. The monthly contribution you paid was correct for the base you chose, but if your real income falls into a higher bracket and your base ended up below that bracket's minimum, Social Security bills you the difference.

No. If you contributed above what you were due, the refund is automatic: Social Security pays you the difference automatically, with no paperwork on your part, before 30 April of the following year.

By adjusting your contribution base throughout the year as you see how your real income is going. You can change your base up to six times a year (effective in March, May, July, September, November and January). If you keep your accounts up to date, you know which bracket you'll fall into before the adjustment.