Your autónomo (self-employed) contribution comes from the contribution base (base de cotización) you choose. That base should follow what you are earning. If your income goes up or down during the year, you can change it up to six times, with set dates on which each change starts to apply. Here are the six windows, the base you can choose in 2026 and when it makes sense to move it. How you choose your first base when you register is in how to register as an autónomo in Spain.
The figures are the 2026 ones and change every year.
Why the law asks you to adjust your base
Since 2023 you contribute according to your net earnings. When you register you choose a base according to what you expect to earn. Afterwards you must change it to keep your contributions in line with your updated forecast (article 308.1.a, rule 3, of the General Social Security Law, Ley General de la Seguridad Social). The law uses the word "deberán" (must). If you do not adjust it, the adjustment comes anyway the following year through the regularización, which compares your average base with your real earnings. We explain it in how the autónomo contribution adjustment works.
Adjusting in time has two advantages. First, you avoid paying a large difference in one go. Second, your base counts for your benefits: the cese de actividad benefit (the self-employed unemployment cover), for example, is calculated from the average of your bases over the previous twelve months (article 339.1). A base that stays too low for months lowers that average.
The six windows of the year
You can change your base up to six times a year. You ask the Social Security Treasury (Tesorería General de la Seguridad Social) and the change takes effect on a date that depends on when you ask (article 45.1 of Real Decreto 2064/1995, the contributions regulation):
| If you apply between | It applies from |
|---|---|
| 1 January and the last day of February | 1 March |
| 1 March and 30 April | 1 May |
| 1 May and 30 June | 1 July |
| 1 July and 31 August | 1 September |
| 1 September and 31 October | 1 November |
| 1 November and 31 December | 1 January of the following year |
Outside these dates there are no shortcuts: a change requested on 2 March does not apply until 1 May. If you see a change in your income coming, apply before the current window closes.
With the request you declare the average monthly net earnings you expect for the year in which the change applies (article 45.2). In practice you do it in Import@ss, the Treasury's online portal, with a digital certificate or Cl@ve.
Which base you can choose in 2026
When you change it you can pick any base between the minimum of bracket 1 of the reduced table and the maximum of the highest bracket of the general table (article 44.4 of Real Decreto 2064/1995). In 2026 that runs from €653,59 to €5.101,20 a month. The sensible choice is a base inside the bracket that matches what you expect to earn, because that bracket is the one used in the adjustment.
In 2026 the 2025 tables apply (article 3.4 of Real Decreto-ley 3/2026) and Orden PJC/297/2026 sets them out in its article 18.1. The contribution in the last column comes from applying 31,5% to the minimum base: 28,3% for common contingencies, 1,3% for occupational contingencies, 0,9% for cese de actividad, 0,1% for vocational training and 0,9% for the intergenerational equity mechanism (articles 18 and 37 of the Orden).
| Bracket | Net earnings per month | Minimum base | Maximum base | Contribution at the minimum base |
|---|---|---|---|---|
| Reduced 1 | Up to €670 | €653,59 | €718,94 | €205,88 |
| Reduced 2 | From €670 to €900 | €718,95 | €900,00 | €226,47 |
| Reduced 3 | From €900 to €1.166,70 | €849,67 | €1.166,70 | €267,65 |
| General 1 | From €1.166,70 to €1.300 | €950,98 | €1.300,00 | €299,56 |
| General 2 | From €1.300 to €1.500 | €960,78 | €1.500,00 | €302,65 |
| General 3 | From €1.500 to €1.700 | €960,78 | €1.700,00 | €302,65 |
| General 4 | From €1.700 to €1.850 | €1.143,79 | €1.850,00 | €360,29 |
| General 5 | From €1.850 to €2.030 | €1.209,15 | €2.030,00 | €380,88 |
| General 6 | From €2.030 to €2.330 | €1.274,51 | €2.330,00 | €401,47 |
| General 7 | From €2.330 to €2.760 | €1.356,21 | €2.760,00 | €427,21 |
| General 8 | From €2.760 to €3.190 | €1.437,91 | €3.190,00 | €452,94 |
| General 9 | From €3.190 to €3.620 | €1.519,61 | €3.620,00 | €478,68 |
| General 10 | From €3.620 to €4.050 | €1.601,31 | €4.050,00 | €504,41 |
| General 11 | From €4.050 to €6.000 | €1.732,03 | €5.101,20 | €545,59 |
| General 12 | Over €6.000 | €1.928,10 | €5.101,20 | €607,35 |
The earnings in the table are countable earnings: your IRPF (personal income tax) net business income plus the autónomo contributions you paid, minus 7% for generic expenses, turned into a monthly average (article 308.1.c of the General Social Security Law). Examples for each bracket are in Social Security contributions for autónomos.
Who cannot choose just any base
- Directors and controlling shareholders of a company, worker-members of sociedades laborales under family control and family members who work with an autónomo. They cannot choose a base below the minimum of group 7 of the general employee scheme (article 308.1.a, rule 4), which in 2026 is €1.424,40 a month (article 3 of Orden PJC/297/2026). We cover it in what an autónomo societario is.
- Anyone on the tarifa plana (reduced flat rate for new autónomos). While you pay the reduced contribution, your base is the minimum of bracket 1 of the general table and choosing a base does not apply (articles 44.3.f and 44.4 of Real Decreto 2064/1995). When it ends you contribute on the base that corresponds to you. More in what the tarifa plana is and how to apply.
An example of a mid-year increase
Imagine you started 2026 expecting net earnings of €1.400 a month. You are in general bracket 2 and contribute on €960,78, a contribution of €302,65. In April you see the year will go better and you will end with an average of about €2.200: general bracket 6, with a minimum base of €1.274,51 and a contribution of €401,47.
- If you apply in April, the change applies from 1 May. From January to April you contributed €313,73 below the new base. The adjustment will ask you for €313,73 × 4 × 31,5% = €395,30.
- If you do nothing, the difference covers all twelve months: €313,73 × 12 × 31,5% = €1.185,90, payable in one go when the adjustment arrives.
The adjustment compares the average of your bases for the year with your bracket, not month by month (article 46.2 of Real Decreto 2064/1995). If for the remaining months you choose a base somewhat above the bracket's minimum, the average can end up inside it and there will be nothing to adjust.
Lowering your base when you earn less
If your income falls, lowering your base cuts your contribution from the effective date. If you do not lower it and you pay above the maximum base of your real bracket, the adjustment will refund the excess, but only down to that maximum base and before 30 April of the year after the one in which Hacienda (the tax agency) reports your earnings (article 308.1.c, rule 4, of the General Social Security Law). If you want the money in your account this year, lower it yourself.
Before you lower it, think about benefits: sick leave pay and cese de actividad are calculated from your bases, so a lower base also means a lower benefit.
Knowing what you have earned so far
To choose well you need to know your net income as the year goes on. In Facturaz your invoices and expenses become your modelo 303 and modelo 130 every quarter, so you see what you have earned before each window closes. With Autónomo Go (€24 + IVA a month) you file the returns yourself with everything prepared. With Autónomo Plus (€44 + IVA a month) our team files them. Both plans come with 14 days free on pricing for autónomos.
