How to work out your employees' overtime (with examples)

Published on 20 February 2026

Overtime is one of the main sources of disputes (and of penalties) in small companies. Knowing how to work it out properly is key to paying fairly and complying with the law. We explain it with worked examples so that no doubt is left.

What overtime is

An hour of overtime is, under article 35.1 of the Estatuto de los Trabajadores, one worked «sobre la duración máxima de la jornada ordinaria de trabajo» — over and above the maximum length of the ordinary working day. That length is whatever your collective agreement or your contract sets, with a legal ceiling of 40 hours a week on average over the year (article 34.1). If your employee has a 40-hour week and works 43, those 3 hours are overtime.

One note, because much has been written about it: the maximum legal working week is still 40 hours. The reduction to 37.5 hours has not been approved or published in the BOE, so the calculation of overtime has not changed.

Legal limits

• A maximum of 80 hours of overtime a year per worker (article 35.2). For anyone whose annual hours are lower than the company's general figure, that maximum is reduced in the same proportion.
• Hours compensated with rest within the 4 months following when they were worked do not count.
• Nor do hours worked to prevent or repair incidents and other extraordinary and urgent damage count, either towards the maximum working day or towards the cap of 80 (article 35.3). Note: they are still paid or compensated as overtime, and those ones are compulsory for the worker.
• Working overtime is voluntary, unless it has been agreed in a collective agreement or in the contract (article 35.4).
• Under-18s may not work overtime (article 6.3). Nor may night workers (article 36.1).
• Part-time contracts may not work overtime except in the incident case in 35.3 (article 12.4.c): what they have is complementary hours, which have rules of their own.

Are they paid or compensated with time off?

Article 35.1 lets you choose «mediante convenio colectivo o, en su defecto, contrato individual» — by collective agreement or, failing that, by individual contract:

• Paying them: at whatever amount is set, which may in no case be lower than the value of an ordinary hour. Any premium above that floor is set by the collective agreement, if it sets one: there is no statutory percentage.
• Compensating them with rest: with equivalent periods of paid rest.

And here is the detail most people assume the wrong way round: if there is no agreement, they are not paid, they are compensated. Article 35.1 ends by saying that «en ausencia de pacto al respecto, se entenderá que las horas extraordinarias realizadas deberán ser compensadas mediante descanso dentro de los cuatro meses siguientes a su realización» — in the absence of any agreement on the point, overtime worked is to be compensated with rest within the four months following. Payment in money is the option that has to be agreed, not the one that applies by default.

How to work them out, with an example

Imagine an employee on a salary of €18,000 a year and 1,800 annual hours. The premium in the example is made up: the one that applies is set by your collective agreement, and many set none, in which case the legal floor is the value of an ordinary hour.

• The value of an ordinary hour: 18,000 ÷ 1,800 = €10.
• If their collective agreement paid overtime with a 25% premium: €10 × 1.25 = €12.50 per hour of overtime.
• If in one month they work 6 hours of overtime: 6 × 12.50 = €75 to pay, plus its contributions.

The record and the communication: three separate obligations

Three things get mixed up here that the law treats separately, and it is worth being clear about them because each one is breached in its own way:

• The daily record of working hours in article 34.9: the start and end of each person's working day, every day, kept for 4 years.
• The overtime record in article 35.5: «la jornada de cada trabajador se registrará día a día y se totalizará en el periodo fijado para el abono de las retribuciones, entregando copia del resumen al trabajador en el recibo correspondiente» — each worker's hours are to be recorded day by day and totalled in the period set for paying wages, with a copy of the summary given to the worker with the corresponding payslip. In other words: here you do have to hand over a copy, normally with the payslip.
• The monthly communication to the workers' legal representatives: the third additional provision of Real Decreto 1561/1995 gives them the right «ser informados mensualmente por el empresario de las horas extraordinarias realizadas, cualquiera que sea su forma de compensación» — to be informed monthly by the employer of the overtime worked, whatever form its compensation takes — receiving a copy of those summaries.

They are independent and compatible obligations, as the Ministry of Labour's guide points out, although the same record can serve for the first two. And do not forget that overtime paid attracts social security contributions: that, and not the fine for the record, is where an inspection gets expensive.

Without a reliable record you cannot prove how much overtime has been worked, the worker cannot claim it, and you cannot defend yourself in an inspection.