Overtime Pay Calculator UK

One of the most common misunderstandings about overtime in the UK is that employers have to pay a premium rate for it. They don't. There's no legal right to time and a half, double time, or any enhanced rate at all. What you're paid for overtime comes down entirely to your contract, and some contracts don't require overtime to be paid at a premium, or in some cases even worked at all.

This calculator works out your gross overtime pay based on your rate and hours, then shows what actually lands in your account after tax and National Insurance, using 2026/27 tax year rates.

The three common overtime arrangements

Voluntary overtime — your employer offers extra hours, and you can choose whether to work them. This is the most common arrangement and gives you the choice each time.

Compulsory guaranteed overtime — your contract says your employer must offer overtime and you must work it. Refusing could be a breach of contract.

Compulsory non-guaranteed overtime — your employer doesn't have to offer overtime, but if they do, your contract requires you to work it.

Which category your overtime falls into matters not just for whether you can refuse it, but for how your holiday pay should be calculated, more on that below.

Common overtime pay rates

Where employers do pay enhanced rates, the typical arrangements are:

• Time and a half (1.5x) — common for evening, weekend, or beyond-contracted-hours work
• Double time (2x) — often reserved for bank holidays or unsociable shifts
• Flat rate — your normal hourly rate for all hours, increasingly common
• Time off in lieu (TOIL) — extra time off instead of extra pay

None of these are legal requirements. Check your contract, staff handbook, or any collective agreement that covers your workplace to find out what applies to you.

How overtime is taxed

Overtime pay is added to your normal pay for the period and taxed together. There's no separate overtime tax rate. The 2026/27 bands are:

Employee National Insurance applies at 8% on earnings between £242 and £967 a week, and 2% above that.

A heavy overtime month can temporarily push you into a higher tax band under PAYE, since the system may treat that month's pay as your new normal. If that happens, it usually balances out automatically over the following pay periods.

Worked example

Say you're paid £14 an hour and work 20 hours of overtime in a month at time and a half:

• Overtime rate: £14 x 1.5 = £21 an hour
• Gross overtime pay: 20 x £21 = £420
• If you're a basic rate taxpayer, roughly 20% Income Tax (£84) and 8% National Insurance (£33.60) come off that
• Take-home from the overtime: approximately £302

If your normal salary already puts you near the £50,270 higher rate threshold, some of that £420 could instead be taxed at 40%, reducing the take-home further.

Overtime and the National Minimum Wage

Whatever your overtime arrangement, your average pay across all hours actually worked must not fall below the National Minimum Wage for your age group. This matters particularly for salaried workers doing significant unpaid overtime: if your salary divided by your total hours worked drops below the minimum wage, your employer is breaking the law, and HMRC enforces this.

Overtime and holiday pay

If you work regular overtime, whether guaranteed or non-guaranteed but regularly worked, it should generally be included when your holiday pay is calculated. Holiday pay is meant to reflect your normal earnings, not just your basic contracted pay. If you consistently work overtime but your holiday pay is based only on basic hours, it may be worth querying with your employer.

Can my employer force me to work overtime?

Only if your contract says so. Even then, your total working time is subject to the Working Time Regulations, which cap average weekly working hours at 48 (averaged over 17 weeks) unless you've signed an opt-out. You can cancel an opt-out at any time by giving notice.

This is general guidance, not legal or financial advice. For a contractual dispute over overtime, check your terms of employment or contact Acas.