Irene Soler is a sworn translator in Zaragoza. She registered in January with the RETA (the Spanish Social Security scheme for the self-employed) and, when she filled in the procedure, she had to tick an estimate of her earnings without yet knowing how much work she would get. She chose a low bracket "just in case". By December she has invoiced 42,000 €, has had 12,000 € of deductible expenses and has paid 3,600 € in contributions over the year. Her question is no longer how much she pays each month, but how much the Tesorería (the Social Security treasury, which collects contributions) will claim from her when the year is regularised.
The short answer: the self-employed contribution is not a fixed amount. Since 2023 contributions have been based on actual earnings, with a provisional base that you choose and a definitive base that is worked out afterwards from the figures in your income tax return.
The base is chosen from a table and the rate is set by law
Article 308 of the General Social Security Act provides that the self-employed contribute "according to the annual earnings obtained" from their activities. Each year the State Budget Act approves two tables: a general one and a reduced one for people who expect earnings below the first bracket of the general table. Each table is divided into brackets of monthly net earnings, and each bracket has a minimum and a maximum base.
The monthly contribution is the result of applying to the chosen base the contribution rates that the Budget Act also sets each year: common contingencies, occupational contingencies, cessation of activity and vocational training. That is why we do not give a contribution figure on this page: it depends on the bracket, on the base you choose within it and on that year's rates, and any amount published without those three references goes out of date as soon as the budget changes.
| Element | Who sets it | When it changes |
|---|---|---|
| Earnings brackets | Budget Act | Every year |
| Minimum and maximum base of each bracket | Budget Act | Every year |
| Base chosen within the bracket | You, when you register or later | Several times a year |
| Contribution rates | Budget Act | Every year |
| Definitive base | The Tesorería, using the figure from Hacienda | When the year is regularised |
Which earnings count for Social Security
You do not contribute on what you invoice, nor simply on your accounting profit. Rule 1 of article 308.1.c takes the net earnings from the activity calculated under the rules of IRPF (Spanish personal income tax) and, under the direct assessment method, adds back the owner's own Social Security contributions. Then rule 2 subtracts a deduction for general expenses of 7 %, which falls to 3 % for the company self-employed (the autónomo societario, a partner or director who must register because of their role in a company).
The reason for adding the contributions back is to avoid a circle: the contribution is a deductible expense for IRPF, but it cannot reduce the earnings used to calculate it.
Irene's figures, step by step
- Income for the year: 42,000 €.
- Deductible expenses other than the contribution: 12,000 €.
- Contributions paid to the RETA: 3,600 €, also deductible for IRPF.
- Net earnings for tax purposes: 42,000 − 12,000 − 3,600 = 26,400 €.
- The contributions are added back: 26,400 + 3,600 = 30,000 €.
- Deduction for general expenses of 7 %: 30,000 × 0.93 = 27,900 €.
- Monthly average: 27,900 ÷ 12 = 2,325 €.
Those 2,325 € a month are what is placed in that year's general table to find which bracket Irene is in. If the base she contributed on provisionally is below the minimum base of that bracket, she will have to pay the difference. Had she contributed above the maximum base of the bracket, the Tesorería would refund the excess.
The calculation requires the year's accounts to be closed. An expense that is later disallowed in a check by Hacienda (the Spanish tax office) raises the earnings and, with them, the contribution base. The relationship between the two administrations is explained in more detail in the guide on contributions based on actual income.
The regularisation arrives late and has its own deadline
Hacienda sends the Tesorería the relevant earnings once the IRPF return has been filed. With that figure, the Tesorería sets the definitive base for each month and compares:
- If you paid too little, you must pay the difference by the last day of the month following notification of the result. Under rule 4 of article 308.1.c, there is no late-payment interest or surcharge within that period.
- If you paid too much, above the maximum of your bracket, the refund is made automatically and without interest, before 30 April of the year after the one in which Hacienda sent the earnings.
- If your provisional base fell within the correct bracket, between its minimum and its maximum, there is no regularisation.
In practice, quite a long time can pass between the year you contributed for and the letter from the Tesorería. It is sensible to keep cash aside for that difference if you know you have chosen a lower bracket than your reality.
Rule 5 of article 308.1.c provides that, if the self-employed person does not file the IRPF return, or files it without declaring income from the activity under the direct assessment method, the definitive base will be the minimum base for common contingencies of contribution group 7 of the General Scheme. It is not a penalty, but it is a floor applied without regard to what you actually earned, and failing to file also has its own tax consequences.
Changing the base during the year
Rule 3 of article 308.1.a requires you to adjust the base as your forecasts change. The rules allow several changes a year, taking effect on set dates. Irene, seeing in June that her invoicing was well above what she had expected, could have moved up a bracket and avoided the whole difference building up for the regularisation.
You do not have to get it right to the euro. The reasonable aim is for the chosen bracket to be consistent with what your books show at any given moment. A very low bracket kept all year only pushes the payment into the future, and a very high one pays money in advance that will take time to come back.
If you are preparing to register and want your initial bracket to be based on a reasoned forecast rather than a hunch, you can send us the details through the self-employed registration form: the activity, expected clients, fixed costs and whether or not you have another source of income.
Situations that alter the general calculation
In some cases the contribution does not follow the mechanics above, or follows them with nuances:
| Situation | What changes |
|---|---|
| First year with a reduced contribution | A fixed contribution with no regularisation for the first twelve months (art. 38 ter LETA) |
| Company self-employed | Minimum base tied to group 7 and general expenses of 3 % |
| A salaried job alongside the activity | Possible refund of part of what was paid for common contingencies |
| Registration by the authorities or late registration | Minimum base of bracket 1 for the earlier months, with no regularisation |
| Several activities | A single RETA registration; all earnings are added together |
LETA is the Self-Employed Workers' Statute Act. Each of these situations has its own explanation: the flat-rate contribution, the company director, a salary plus an activity and a late registration.
What is not regularised
Two warnings about the small print. First: contributions you did not pay within the voluntary period, calculated on the provisional base, are neither refunded nor changed even if the definitive base turns out lower; and surcharges and interest are never refunded. Second: if Hacienda later reviews your IRPF and the earnings go up, the Tesorería informs the Labour Inspectorate so that it can regularise. If the earnings go down because of a correction in your favour, you can ask for a refund of what you paid in excess.
This means that the self-employed contribution stays open for as long as the IRPF for the same year does. Any tax correction has an echo in your contributions, and it is worth bearing that in mind when deciding whether to correct a self-assessment or to accept a proposal from Hacienda.
What to have to hand each quarter
To keep the provisional base from drifting away from reality, a simple quarterly review is enough: income to date, expenses to date, a projection to the end of the year and a comparison with the bracket you have chosen. The same information is used for the instalment payment on Modelo 130, so it is not extra work but a different reading of the same numbers. The calendar of forms for the first year sets out those dates.
Irene, with a monthly average of 2,325 €, can check when the results are published whether her provisional bracket was too low and prepare the payment. If in doing so she finds expenses that were not recorded, the correction must be made in the IRPF, which is where Social Security draws its figures from, not directly with the Tesorería.
At Salama Tax we review the earnings forecast when the activity is registered and compare it with the books every quarter, because the contribution bracket and the IRPF instalment payment come from the same figures and must tell the same story.