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How are UK bonuses taxed?

By the PaySlipCheck Editorial team · 19 May 2026 · 7 min read

UK bonuses are taxed at exactly the same rates as your salary — Income Tax at 20%/40%/45% plus NI at 8% or 2%. The reason your payslip shows what looks like 50% deductions in a bonus month is that PAYE catches up nine months of higher-rate tax in one go. Your year-end tax position is correct; only the monthly profile is misleading.

The myth: "50% bonus tax"

You ask HR about the £10,000 bonus they've signed off. The payslip arrives and you've taken home £4,800 of it. The other £5,200 went somewhere. You assume the UK has a special punitive rate for bonuses. It doesn't. What you're looking at is the way HMRC's cumulative PAYE system pulls your year-to-date tax position back into line in the month the bonus arrives.

The reality: cumulative PAYE

UK Income Tax under PAYE is calculated on the year-to-date, not on each pay period in isolation. Each month your employer:

1. Adds up your total earnings for the tax year so far (the "cumulative" figure).
2. Works out how much Income Tax you'd owe on that cumulative figure if it were your full year's income.
3. Pro-rates that to the fraction of the year that's elapsed (5/12 if you're in Month 5, 9/12 if you're in Month 9, etc.).
4. Subtracts the tax you've already paid in previous months.
5. Deducts the difference from this month's pay.

For a steady salary this produces an identical deduction every month. For a bonus month, your year-to-date jumps massively, the cumulative calculation says "this person should be a higher-rate taxpayer for the whole year," and one month catches up several months of higher-rate tax all at once.

Worked example: £40,000 salary + £10,000 bonus in December

Without the bonus, this person's annual Income Tax is £5,486 (basic rate on £40,000 − £12,570). Monthly tax: about £457.

With the £10,000 bonus, total annual income is £50,000. Annual Income Tax: £7,486 (still all basic rate since £50k is just under the £50,270 threshold). Monthly tax averaged: £624.

So the bonus itself triggers £2,000 of extra Income Tax over the year (20% of £10,000). But it lands in one month — December (Month 9 of the tax year).

December's £1,959 in tax looks like a 14.7% rate on the £13,333 gross — and it is, in that month. But this is purely cumulative catch-up. The bonus itself was taxed at exactly 20% (£2,000 on £10,000) when you look at the year as a whole.

For your specific numbers, the bonus tax calculator works out both the year-end true rate and the month-of-payment feels-like rate.

What happens at higher salaries

If the bonus pushes you over the higher-rate threshold (£50,270 in 2025/26) the slice above £50,270 is taxed at 40%, not 20%. NI on the same slice drops from 8% to 2% (the upper earnings limit also sits at £50,270).

So a £100,000-earner getting a £30,000 bonus pays:

• £12,000 Income Tax on the bonus itself (40% × £30,000)
• £600 NI on the bonus (2% × £30,000)
• Total: £12,600 — leaving £17,400 of the £30,000 bonus.

The 60% trap and bonuses

Bonuses that push your total income through the £100,000–£125,140 personal-allowance taper get hit with an effective marginal rate of 62%. If you're paid £95,000 plus a £20,000 bonus, the slice from £100,000 to £115,000 disappears at 62p in the pound.

The single most effective tax-avoidance move for bonuses near this range is bonus sacrifice into pension. If your employer allows it, the bonus never appears as taxable income, never tapers your allowance and never gets hit at 62%. Instead it goes straight to pension at full value. For higher earners this is a no-brainer — see the £100,000 after tax page for the full mechanics of the trap.

NI on bonuses is different (and worse in one specific case)

National Insurance is not cumulative. It's calculated separately per pay period using monthly thresholds. So a bonus in a single month:

• Uses up the monthly Primary Threshold (£1,048) only once that month, not pro-rated.
• Uses up the monthly Upper Earnings Limit (£4,189) only once.
• Means more of the bonus crosses into the 2% NI band rather than the 8% band — actually slightly reducing NI compared to spreading the same total over the year.

For most people this is a tiny effect. But it means there's no year-end NI reconciliation: whatever you paid in the bonus month stays paid.

Student loan and bonuses

Student loan deductions are also non-cumulative — based on the income in each pay period above that period's threshold. So a £10,000 bonus that pushes that month's gross from £3,333 to £13,333 triggers a student-loan deduction of about £972 in that month alone (9% of the slice above the monthly threshold of £2,373 for Plan 2). Across the year this evens out approximately — there's no formal reconciliation but the total paid roughly matches what you'd owe if the bonus had been spread.

How to keep more of your bonus

1. Sacrifice into pension

If your employer offers bonus sacrifice, this is the cleanest tax break in the UK system. For a higher-rate taxpayer:

• £10,000 cash bonus → £5,800 in your bank after 40% tax + 2% NI
• £10,000 bonus sacrifice → £10,000 in your pension

For someone above £100k, the saving is even more dramatic because pension sacrifice rescues the personal allowance from being tapered.

2. Max out your ISA

£20,000 a year tax-free. After-tax bonus into a Stocks & Shares ISA grows tax-free and the dividends come out tax-free. Won't reduce the tax on the bonus itself but it stops future earnings being taxed.

3. Pay off expensive debt first

Credit card debt at 25% APR is a guaranteed 25% pre-tax return when paid off. Better than any investment.

4. Top up your emergency fund

Boring, but the point of a bonus is optionality. Three to six months of essential outgoings in cash means a future job loss doesn't force a panicked decision.

For the longer thinking on what to do with a lump sum — drip-feed vs lump-sum investing, paying down the mortgage vs investing the difference, the case for a one-off splurge — PennyWise Finance has a deeper piece on smart things to do with a bonus.

When you'll actually receive the bonus

HR's "January bonus" usually lands in the January payroll run — depending on your pay date that could be 15 Jan, 25 Jan, last working day of the month, etc. The PAYE month (Month 10) runs 6 January – 5 February, so a January bonus is taxed against your year-to-date through Month 10.

If your employer pays bonuses in March (Month 12), the cumulative catch-up has the entire rest of the year compressed into that single payslip — which is why March bonuses look the most punitive on paper. They aren't actually worse; they're just maximally cumulative.

Related: Bonus tax calculator · £100,000 after tax — the 60% trap · Salary sacrifice calculator · Why your take-home changes month-to-month