Firefighter overtime after tax 2026/27: what you keep

The simple method: work out the marginal rate

Most people ask what percentage of overtime is taken as tax, and the accurate answer is the marginal rate: what happens to the next pound you earn on top of everything else. Overtime is employment income added to basic pay, so it is taxed at whatever rate applies to the top slice of your income, plus National Insurance, plus any pension contribution that applies to it. Applying your average tax rate to overtime understates the deduction for some people and overstates it for others.

For a basic-rate taxpayer in England, Wales or Northern Ireland in 2026/27, the marginal rate is 20% income tax plus 8% employee National Insurance, so 28p of each extra pound is deducted and 72p is kept. In Scotland the equivalent is 21% (the intermediate band) plus 8%, or 29%, at a competent firefighter's income, and higher Scottish bands begin as earnings rise. Above £50,270 of pay, National Insurance falls to 2%, so the deduction for a higher-rate English taxpayer is 40% plus 2%.

The rest of this guide puts real numbers on those rules using the 2026/27 rates from HMRC, and the NJC pay figures effective 1 July 2026. For the gross rates that overtime is built from, see firefighter overtime rates.

Worked example: competent firefighter, England

Start with a wholetime competent firefighter in England on £40,358, paying the 12.59% FPS 2015 contribution and with a standard tax code. The annual baseline is: pension £5,081.07, income tax £4,541.39, National Insurance £2,223.04 and net pay £28,512.50. Now add overtime that is not pensionable.

At £1,000 of overtime, income tax rises by £200 and National Insurance by £80, so net pay rises by £720. At £3,000 the net gain is £2,160, at £5,000 it is £3,600, and at £10,000 it is £7,205 because National Insurance on the last £88 of that overtime is only 2%. The higher-rate threshold is a long way away: taxable income after pension would need to reach £50,270, which requires about £14,993 of extra pay at this salary.

Scotland: different income tax bands

Scottish income tax uses six bands for earned income: 19%, 20%, 21%, 42%, 45% and 48%. Firefighters in the Scottish Fire and Rescue Service therefore see a different marginal rate from colleagues elsewhere in the UK, and the difference is more pronounced at higher salaries. The National Insurance system is UK-wide, so the 8% and 2% rates are the same.

Take the same £40,358 salary with the Scottish FPS 2015 contribution rate for that pay level (13.63%). The baseline net is £28,163.08 a year. Adding £1,000 of non-pensionable overtime raises net pay by £710, because the marginal rate is 21% income tax plus 8% National Insurance. At £5,000 the gain is £3,550, and at £10,000 it falls to £6,854 as part of the extra pay crosses into the 42% band.

Watch managers and the National Insurance drop

Managers sit on higher salaries, so their overtime interacts with the National Insurance upper limit. A watch manager at competent B earns £50,034 a year and pays 14.09% pension in England, which leaves taxable income after pension of £42,984: still within the basic-rate band. Their overtime is therefore taxed at 20%, but because their pay crosses £50,270, most of the overtime attracts only 2% National Insurance.

With £3,000 of non-pensionable overtime the watch manager's net rises by £2,326, or 77.5%. With £5,000 it rises by £3,886, or 77.7%. That is a better ratio than the firefighter's, and it illustrates why 'higher earners are taxed more heavily on overtime' is not always true: it depends where the overtime lands relative to thresholds. It also depends on the pension treatment discussed next.

What if overtime is pensionable?

The examples above assume overtime does not count as pensionable pay. If your overtime is pensionable, a contribution comes out of it as well. Take the competent firefighter with £2,000 of pensionable overtime: pensionable pay becomes £42,358, still within the 12.59% English band, so the pension contribution rises by about £252 to £5,333. Net pay rises by £1,239 instead of £1,440, meaning you keep about 62p of each pound instead of 72p, but the £2,000 also builds pension.

Under FPS 2015 in England each year's pensionable pay divided by 59.7 is added to your pension account, so £2,000 of extra pensionable pay adds roughly £33 of annual pension for that year. The trade-off is a lower take-home figure now for extra retirement income later, which many members value, particularly because contributions receive income tax relief. Whether your overtime counts is a question for your administrator: see the FPS 2015 guide and contribution bands.

Contribution bands in England now depend on actual pensionable earnings. A large amount of pensionable overtime could push you across a band boundary such as £45,407, at which the rate would rise to 14.09%. Use the pension contributions calculator to see where your total pensionable earnings put you.

Why one payslip can look harsher than the annual picture

PAYE income tax is cumulative for most tax codes: each pay period, payroll compares your pay to date with the allowance and bands to date and works out tax due. National Insurance, by contrast, is normally calculated per pay period, using monthly thresholds. This means a month with a large overtime payment, or with several backdated payments at once, can show a higher National Insurance deduction than the annual average suggests.

Backdated pay and arrears matter too. If the July 2026 award or an overtime claim arrives late, it is paid with the current period's earnings, and the National Insurance calculation is done on that period alone; see the 2026 pay rise guide for how arrears work. The sum that eventually matters is the annual position, and HMRC reconciles income tax over the year.

If a payslip looks wrong, compare gross first, then deductions. The payslip checker compares your inputs with expected tax, National Insurance and pension for the year and helps you tell an unusual month from a mistake.

Other deductions that can change the answer

Student loan and postgraduate loan repayments are calculated on earnings above their thresholds, so extra overtime can increase repayments, and they are not included in every quick calculator. Check the current thresholds on GOV.UK for your plan type. Overtime that lifts your pay might also matter for the High Income Child Benefit Charge, which starts when adjusted net income goes above a threshold set by HMRC (£60,000 at the time of writing; check GOV.UK); see high income child benefit charge for firefighters.

If you use salary sacrifice or a cycle-to-work arrangement, those reduce taxable pay before overtime is added, which slightly changes the marginal maths; see firefighter salary sacrifice schemes and the cycle-to-work calculator. Firefighters who receive means-tested benefits should also check how extra income affects them; the guide on overtime and Universal Credit covers the principles.

Finally, overtime is unpredictable. Lenders may not count all of it for a mortgage, so use basic pay for affordability and treat overtime as a saving accelerator; the overtime-to-deposit tool shows how quickly it could add up.

Overtime tax myths worth ignoring

The most common myth is that 'overtime is taxed at a higher rate'. There is no overtime tax rate. Overtime is just more income in the same tax year, and the rate on it is your marginal rate. If your total taxable income stays within the basic-rate band, overtime is taxed at 20% in England, Wales and Northern Ireland, exactly the same as basic pay.

A second myth is that doing overtime can leave you worse off overall because it pushes you into a higher band on all your income. That is not how UK income tax works: only the slice of income above a threshold is taxed at the higher rate. Crossing a threshold increases the rate on the additional pound, never on the pounds beneath it. The exceptions are specific charges and tapers, such as the High Income Child Benefit Charge and the personal allowance taper above £100,000, which have their own rules.

A third is that a single low-looking payslip means you have been overtaxed. Because PAYE is cumulative for income tax and periodic for National Insurance, a bumper month can look unusual and a quiet month can look generous. The way to check is to compare the annual tax and National Insurance to date with expected figures for your total gross pay, which is what the payslip checker does.

Planning: how many hours to hit a take-home target

Work backwards from a net target. If you want an extra £2,000 a year take-home as a competent firefighter in England, you need about £2,778 gross overtime (£2,000 ÷ 0.72). At £27.65 an hour that is about 100 hours. As a competent Scottish firefighter, £2,000 net needs about £2,817 gross (÷ 0.71), or roughly 102 hours.

Spread across a year, 100 hours is under two hours a week, which puts a small extra income in context. But rest matters: night duties, fatigue and working-time limits all affect what is sensible, and your service may set limits on extra hours; read shift patterns and the 42-hour week and the guide on second jobs. For a per-role picture use the pay scales.