Overtime pay in UK employment contracts: when it is compulsory and when it is not

Your manager messages you at 4pm on a Thursday: the deadline has moved, can you stay late tonight and come in on Saturday? You want to pull your weight, but two questions run through your head before you reply. Will you actually be paid for those extra hours, and can you say no?

Here is the blunt answer. In the UK there is no automatic legal right to be paid extra for overtime. Whether you are paid at all, and whether you get a higher rate for it, comes down to what your contract says. The one hard floor is the National Minimum Wage: your average pay across every hour you actually work cannot drop below it, however much unpaid overtime you put in.

Key takeaways

• There is no statutory right to overtime pay, and no legal right to an enhanced "time and a half" rate. Your contract sets the terms.
• Your average hourly pay across all hours worked must never fall below the National Minimum Wage.
• Whether you have to work overtime depends on whether your contract makes it compulsory (guaranteed or non-guaranteed) or voluntary.
• You cannot be made to work more than 48 hours a week on average unless you have signed an opt-out, which you can later withdraw.
• Regular overtime should be reflected in at least part of your holiday pay, a point many payslips get wrong.

Is overtime paid in the UK? The honest answer

Employers do not have to pay you for overtime. That is the position set out on gov.uk. The right to be paid for extra hours, and the rate you get, live entirely in your employment contract.

In practice, contracts handle this in a few different ways. Some pay overtime at your normal hourly rate (often called plain time). Some pay an enhanced rate, such as time and a half or double time for weekends and bank holidays. And some, particularly for salaried staff, pay nothing extra for hours beyond your contracted total, because the contract says your salary covers "all hours reasonably required to fulfil the role".

None of those approaches is unlawful in itself. The question is which one applies to you, and the only way to know is to read the clause.

The one floor that always applies: the National Minimum Wage

Even where overtime is unpaid under your contract, there is a limit to how far that can go. Your total pay divided by the total hours you actually work must stay at or above the National Minimum Wage for your age. From 1 April 2026 that rate is £12.71 an hour for workers aged 21 and over.

This matters most if you are salaried and paid close to the minimum. Regular unpaid extra hours lower your effective hourly rate, and once it drops below the National Minimum Wage the arrangement becomes unlawful. It is the same floor that protects hourly staff, including workers on zero-hours contracts, where every hour has to be counted and paid.

💡 Pro Tip: Do a quick sum. Take your gross monthly pay, divide by the hours you genuinely work in a month (contracted hours plus regular unpaid overtime), and check the result against £12.71. If you are near or below it, you have a real issue to raise, not a vague grievance.

Compulsory or voluntary? What decides whether you must work overtime

"Do I have to work overtime" is the question that causes the most confusion, and the honest answer is: it depends what your contract says. Overtime falls into three broad types.

• Voluntary overtime. Your employer can offer it, and you can turn it down. Neither side is obliged. If your contract says nothing that requires you to work extra hours, this is usually your position.
• Non-guaranteed overtime. Your employer does not have to offer it, but your contract says that when it is offered, you have to work it. This is where refusing can become a disciplinary matter.
• Guaranteed overtime. Your employer must offer the hours and must pay for them, and you must work them. This is the least common arrangement.

So whether overtime is compulsory turns entirely on the wording. A clause such as "you may be required to work additional hours as reasonably necessary to meet the needs of the business" is a compulsory (non-guaranteed) term. Refusing point blank could put you on the wrong side of your contract.

One change is coming that affects this. From 2027 the Employment Rights Act 2025 will require employers to offer a guaranteed-hours contract to qualifying workers on zero or low-hours terms, reflecting the hours they actually work over a reference period. If you are contracted for far fewer hours than you routinely work, that reform is aimed squarely at your situation.

There are limits, though. A requirement to work overtime still has to be reasonable, and it cannot be used to sidestep your other rights. If regular overtime is clashing with caring responsibilities or health needs, you may have grounds to request flexible working rather than simply refuse shift by shift.

The 48-hour limit and the opt-out

Whatever your contract says about compulsory overtime, it sits under a legal ceiling. The Working Time Regulations 1998 cap your average working time at 48 hours a week, measured over a 17-week reference period. Overtime counts towards that average, so a run of long weeks has to be balanced by shorter ones.

You can agree to work more by signing an opt-out, and many contracts include one. If you have signed it, you are agreeing to waive the 48-hour average. What plenty of people do not realise is that you can change your mind: you can withdraw the opt-out by giving your employer notice, at least seven days, and up to three months if your written agreement sets a longer period. You cannot be dismissed or treated unfairly for refusing to sign, or for cancelling.

💡 Pro Tip: The opt-out is often a single line buried in the main contract, sometimes above the signature block, so signing the contract signs the opt-out too. Look for it before you sign, and remember you can withdraw it later even if you agreed at the start.

Overtime and your holiday pay

This is the part most people miss, and it can be worth real money. Holiday pay is meant to reflect your normal pay, not just your basic contracted hours. Where overtime is a regular, settled part of what you earn, it should be included in the calculation for at least the four weeks of statutory holiday that derive from retained EU law.

This is the established position following the Bear Scotland v Fulton line of cases and the "normal remuneration" principle, and amendments to the Working Time Regulations that took effect from 1 January 2024 set out that normal pay for that four-week portion includes payments such as regularly worked overtime. The remaining 1.6 weeks of the 5.6-week statutory minimum can be paid at your basic rate.

In plain terms: if you regularly work paid overtime and your holiday pay is calculated on basic hours only, you may be underpaid every time you take annual leave. It is one of the most common holiday-pay errors, and it is worth checking against your payslips.

Time off in lieu instead of overtime pay

Not every contract pays for overtime in cash. A common alternative is time off in lieu (TOIL), where extra hours are banked and taken back later as paid time off rather than paid at the time.

TOIL is perfectly legal, but the detail matters. Check how it accrues (hour for hour, or at an enhanced rate), whether there is a deadline to use it, and what happens to unused time. If your TOIL expires unused and is never paid out, you have worked those hours for free.

What to check in your contract

Before you commit to a job, or before you agree to a run of overtime, read the relevant clauses closely. Most of what you need to know is in two or three sentences.

Beyond the wording itself, run through this quick checklist:

1. Is overtime paid or unpaid? Find the clause and read it in full, not just the heading.
2. At what rate? Plain time or enhanced, and whether weekends and bank holidays differ.
3. Is it compulsory or voluntary? Guaranteed, non-guaranteed or genuinely optional.
4. Have you signed the 48-hour opt-out? If so, note that you can withdraw it.
5. How does holiday pay treat your overtime? Basic hours only, or your normal pay.

Overtime also sits alongside other working-time and exit terms worth reading with the same care, from your notice period and any garden leave clause to how the contract can be ended under its termination clause.

What to do if you are not being paid correctly

If the maths does not add up, or overtime you were promised has not appeared, work through it in order rather than reaching straight for a tribunal.

1. Check the clause first. Confirm what your contract actually says about overtime pay, rate and holiday pay. You want to be sure of your ground before you raise it.
2. Keep your own records. Log the extra hours you work, the dates, and what you were paid. A simple notes-app record is enough, and it is what any claim would rest on.
3. Raise it in writing. A short, factual message to your manager or HR often resolves a genuine payroll error quickly.
4. Escalate through a grievance if it is not sorted informally.
5. Get free advice from Acas. As a last resort, unpaid wages can be pursued as an unlawful deduction from wages at an employment tribunal. The deadline is three months less one day from the deduction, rising to six months where the deduction falls on or after 1 October 2026 — but do not sit on it either way.

Check the overtime clause before you sign

The rights above are the floor the law gives you. Almost everything else about your overtime, whether you are paid, at what rate, whether you can be made to work it, and how it feeds into your holiday pay, is decided by a contract the employer drafted for the employer's benefit.

You do not need a solicitor to read those clauses. Upload your contract to Ookulli's employment contract review and our AI-powered review, built specifically for UK employment law, will flag whether overtime is paid or unpaid, whether it is compulsory, whether a 48-hour opt-out is buried in the terms, and how holiday pay is calculated, clause by clause, before you commit. Your first contract review is free. After that, reviews are £10 per document with no subscription and a 30-day money-back guarantee, and your document is never used to train AI models.

This content is for informational purposes only and does not constitute legal advice. If you have specific concerns about your contract, consider consulting a qualified solicitor.

Frequently asked questions

Do I have to work overtime?

It depends on your contract. If overtime is voluntary, you can decline. If your contract contains a clause requiring you to work reasonable additional hours when asked (non-guaranteed overtime), then refusing could be a disciplinary matter. Any requirement still has to be reasonable, and you cannot be forced past the 48-hour weekly average unless you have opted out.

Does my employer have to pay me for overtime?

Not automatically. There is no statutory right to overtime pay in the UK, so whether you are paid, and at what rate, depends entirely on your contract. The only legal limit is that your average pay across all the hours you work must not fall below the National Minimum Wage.

Is overtime included in my holiday pay?

For regular overtime, it usually should be, for at least the four weeks of statutory holiday derived from retained EU law. This follows the Bear Scotland case law and the "normal remuneration" principle, reflected in the Working Time Regulations from 1 January 2024. If your holiday pay ignores regular overtime, you may be underpaid.

Can I refuse to work overtime?

If your overtime is voluntary, yes, without consequence. If your contract makes overtime compulsory, refusing could breach it. Even then, your employer cannot require more than an average of 48 hours a week unless you have signed an opt-out, and you can withdraw that opt-out by giving notice.

What is the 48-hour working limit?

Under the Working Time Regulations 1998, your average working time cannot exceed 48 hours a week, calculated over a 17-week reference period. Overtime counts towards it. You can agree to work more by signing an opt-out, which you are free to cancel later with at least seven days' notice, or more if your agreement specifies.

Do I get paid more for overtime, like time and a half?

Only if your contract says so. There is no legal right to an enhanced rate such as time and a half or double time. Some contracts offer it, especially for evenings, weekends and bank holidays, but many pay overtime at your normal hourly rate, and some pay nothing extra for salaried roles. Check the clause before you rely on a higher rate.