Overtime Calculator 🇬🇧

Overtime rules in the UK don’t work the way most people assume. There’s no law that guarantees you time and a half, and the tax on your extra hours isn’t calculated any differently to your normal pay — even though it often feels like it is. Use the calculator above to get your numbers instantly, then read on to understand exactly where those numbers come from, what changed for 2026, and what your employer legally has to do. If you’d rather work out your full monthly or annual take-home first, our UK take-home pay calculator factors overtime straight into your Income Tax and National Insurance.

What Counts as Overtime in the UK?

For a full-time employee on a standard 37.5 or 40-hour week, overtime typically means hours worked past that point. But if you’re part-time and contracted for 20 hours a week, anything beyond those 20 hours is overtime for you — even if a full-time colleague wouldn’t be in overtime territory yet at the same clock time. This distinction matters because it affects both your pay and how those extra hours are treated under the Working Time Regulations 1998.

Overtime generally falls into a few categories:

• Compulsory guaranteed overtime — your employer must offer it and you must work it, as set out in your contract.
• Compulsory non-guaranteed overtime — you must work it if asked, but your employer isn’t obliged to offer it regularly.
• Voluntary overtime — you can accept or decline it freely, with no penalty for saying no.

Which category your overtime falls into isn’t just a technicality — it directly determines whether it has to be included in your holiday pay calculation, which we cover in detail further down. You can check your own entitlement with our holiday entitlement calculator.

Is Overtime Pay a Legal Right in 2026?

This surprises a lot of people, especially those used to systems like the US Fair Labor Standards Act, which mandates time-and-a-half after 40 hours. The UK has no equivalent. An employer can legally ask you to work extra hours at your normal rate, or even offer no extra pay at all, unless your contract says otherwise.

There is one hard limit, though: your average hourly pay, including overtime hours, must never fall below the National Minimum Wage or National Living Wage for your age group. If your employer pays plain time for overtime and that drags your effective hourly rate below the legal minimum, that’s a National Minimum Wage breach — regardless of what your contract says. You can check where you stand with our minimum wage checker.

How to Calculate Overtime Pay, Step by Step

Since there’s no statutory formula, the calculation depends on what your contract says. Here’s the general method:

1. Find your normal hourly rate. If you’re salaried, divide your annual salary by your contracted annual hours (e.g., 52 × 37.5).
2. Check your overtime multiplier. Look at your contract or staff handbook — common multipliers are 1× (plain time), 1.5× (time and a half), or 2× (double time).
3. Multiply your hourly rate by the multiplier, then multiply that by the number of overtime hours worked.
4. Add it to your normal gross pay for the period to get your total gross pay before tax and National Insurance.

If your contract is silent on a multiplier, the default legal position is that overtime is paid at your normal hourly rate — there’s no automatic uplift. Once you’ve got your overtime figure, plug your full pay into the take-home pay calculator above to see the actual amount that lands in your bank account after tax and NI.

Overtime Rates Explained: Time and a Half, Double Time & More

Because rates aren’t set by law, they vary widely by employer and sector. Here’s what’s typical in practice:

2026 National Minimum Wage and National Living Wage Rates

These rates took effect on 1 April 2026 and set the legal floor your average hourly pay, overtime included, must never fall below. Full official figures are on the gov.uk minimum wage rates page.

The National Living Wage increase represents a 4.1% rise, while the 18-20 rate jumped 8.5% as the government continues narrowing the gap between age bands. Zero-hours workers are covered by these rates too: every hour worked, including overtime, must be paid at least the applicable minimum, even though employers aren’t obliged to guarantee minimum hours. Not sure where you stand? Try our National Minimum Wage checker.

How Overtime Is Taxed in 2026 (Income Tax & National Insurance)

The “overtime gets taxed more” myth usually comes from a real but different effect: a big overtime payment in one pay period can temporarily push that period’s pay into a higher tax bracket under PAYE’s cumulative or non-cumulative calculation, making the deduction on that specific payslip look disproportionate. Over the full tax year, it typically evens out, since your total annual tax liability is based on total annual earnings, not any single payslip in isolation.

The Personal Allowance and thresholds have been frozen at these levels since 2022/23, which means pay rises — including regular overtime — are more likely to push people into a higher band than in years when thresholds rose with inflation. This effect is often called “fiscal drag.”

Want to see the exact take-home effect of an overtime shift on your payslip? Run the numbers through our UK take-home pay calculator.

Overtime and Holiday Pay: The 2026 Rules

This is one of the most misunderstood areas of UK employment law. Many employees assume holiday pay is based purely on basic salary, but case law and the Working Time Regulations 1998 (as clarified through subsequent tribunal decisions, and now backed by gov.uk holiday entitlement guidance) require regular overtime to be folded in, so that taking holiday doesn’t leave you financially worse off than working a normal week.

The calculation uses a 52-week reference period: your employer averages your actual pay across the 52 weeks you were paid, looking back up to 104 weeks if needed to find 52 weeks with pay (skipping unpaid weeks). If your overtime is genuinely ad hoc — a single Saturday shift you covered once, with no pattern — it typically doesn’t need to be included. Check your own leave and pay averaging with our holiday entitlement calculator.

The 48-Hour Working Week Limit and Overtime

The 48-hour limit is an average, not a hard weekly cap — you can work 55 hours one week as long as it balances out with lighter weeks over the 17-week window. Once you’ve signed a written opt-out, you can work beyond 48 hours, and you can cancel that opt-out at any time by giving notice (usually 7 days, or up to 3 months if your contract specifies a longer notice period, capped at 3 months by law).

Night workers get extra protection regardless of opt-out status: anyone working at least 3 hours between 11pm and 6am is capped at an average of 8 hours in any 24-hour period, measured over the reference period. Employers must keep records sufficient to demonstrate compliance with the 48-hour limit — this obligation sits alongside, and is separate from, National Minimum Wage record-keeping.

Compulsory vs Voluntary Overtime: Know Your Rights

Worked Examples for 2026

Example 1: Hourly worker, time and a half

Sarah is 24, earns £13.50/hour, and works 5 hours of overtime at time and a half in a week.
Overtime pay = £13.50 × 1.5 × 5 = £101.25 added to her normal gross pay for that week.

Example 2: Salaried employee, plain-time overtime

Tom earns £34,320/year, contracted for 37.5 hours/week (1,950 hours/year). His hourly rate is £34,320 ÷ 1,950 = £17.60. His employer pays overtime at plain time, and he works 6 extra hours this month.
Overtime pay = £17.60 × 1 × 6 = £105.60 added to that month’s gross pay.

Example 3: 20-year-old on the National Minimum Wage

Priya is 20 and earns exactly the National Minimum Wage of £10.85/hour, with no contractual overtime premium. She works overtime at plain time.
Her effective hourly rate for overtime hours is still £10.85 — exactly at the legal floor. If her employer tried to pay her less than £10.85 for those overtime hours, that would be an NMW breach, regardless of contract wording.

Overtime Calculator vs Manual Calculation

A calculator is the fastest way to get an accurate number, but it’s worth understanding the underlying formula — especially if you ever need to query your payslip with HR or challenge an underpayment. Once you have your overtime figure, our take-home pay calculator handles the tax and NI side for you.

Common Overtime Pay Mistakes

• Assuming overtime is legally entitled to a premium rate. Without a contractual clause, plain time is legally sufficient.
• Excluding regular voluntary overtime from holiday pay. This is one of the most common employer errors and a frequent source of tribunal claims.
• Forgetting the NMW “averaging” trap. Paying plain time for overtime can silently breach NMW if the worker is already close to the minimum on their standard hours.
• Ignoring the 48-hour limit for voluntary overtime. Many employers wrongly assume only compulsory overtime counts toward the weekly average.
• Treating TOIL as a way around the 48-hour rule. The hours are still worked, even if paid in time rather than money.
• Not keeping adequate records. Both NMW compliance and the 48-hour limit require documented evidence, not just good intentions.

Expert Tips for Getting Overtime Right

Frequently Asked Questions

Final Verdict

If you want an accurate number fast, the calculator above does the arithmetic for you — but the number is only as good as the inputs. The multiplier your employer actually applies comes from your contract, not from any UK statute, so check that first. Beyond the pay itself, the two things most workers get wrong are assuming overtime is taxed differently (it isn’t) and assuming voluntary overtime doesn’t count toward holiday pay (it often does, if it’s regular).

Conclusion

UK overtime law is built around limits and protections — the 48-hour week, National Minimum Wage compliance, and holiday pay averaging — rather than a guaranteed premium rate. Understanding where your contract sits inside that framework is what actually determines your take-home pay, not a one-size-fits-all national rule. With the Fair Work Agency now operating and NMW rates risen across every age band, it’s a good year for both employees and employers to double-check their overtime arrangements are compliant.

This article reflects rates and rules confirmed for the 2026/27 tax year and 2026 National Minimum Wage cycle, including the Employment Rights Act 2025 and the Working Time Regulations 1998. Figures are provided for general guidance only and don’t constitute legal or tax advice — for your specific situation, consult ACAS, HMRC, or a qualified employment solicitor. Sources: gov.uk – National Minimum Wage rates, gov.uk – maximum weekly working hours, gov.uk – holiday entitlement rights, Working Time Regulations 1998 (SI 1998/1833).