How Bonuses Are Taxed in the UK and US

Your bonus is taxed like any other income — as salary, not as a windfall. That means it's subject to income tax, National Insurance (UK) or FICA (US), and pension contributions, all withheld at your marginal rate (the rate on your next pound of income). The result: that promised £5,000 bonus often nets only £3,100–£3,600. This guide explains exactly how bonuses are taxed, why the deduction surprises most people, and what you can actually expect to take home.

How Bonuses Are Taxed — The Basics

Bonuses aren't taxed at a special rate. They're ordinary earned income, added on top of your salary, and taxed at whatever your marginal rate happens to be. That's the key word: marginal. It's not the average tax you pay across all earnings — it's the tax rate on that specific bonus.

Here's why it matters. If you earn £45,000, your effective (average) tax rate across the year is roughly 18%. But a £5,000 bonus arriving on top of that £45,000 isn't taxed at 18% — it's taxed at 28% (20% income tax + 8% National Insurance, if you're in the basic rate band). The bonus sits entirely in your marginal bracket, which is always higher than your average.

This is by design. The UK tax system is progressive: each additional pound is taxed a bit more than the last. A bonus added to your existing salary sits in the highest bracket you occupy, not spread across all your income. The same logic applies in the US, where a bonus is added to your annual income and taxed at your marginal federal bracket.

UK Bonus Tax — Full Breakdown

Income tax bands (2026):

£0–£12,570: 0% (personal allowance)
£12,570–£50,270: 20% (basic rate)
£50,270–£125,140: 40% (higher rate)
£125,140+: 45% (additional rate)

National Insurance (employee, standard Category A):

£0–£12,570: 0%
£12,570–£50,270: 8%
£50,270+: 2%

Combined marginal rates:

Basic rate: 20% income tax + 8% NI = 28% total
Higher rate: 40% income tax + 2% NI = 42% total
Additional rate: 45% income tax + 2% NI = 47% total

Pension contributions are deducted from your gross pay before tax is calculated, so a £5,000 bonus minus 5% pension (£250) is taxed on £4,750, saving you £50 in income tax. Student loan repayment (Plan 2) is 9% of anything above £27,295, assessed on your total earnings including the bonus.

Example: Basic rate taxpayer, £45,000 salary + £5,000 bonus, 5% pension contribution, Plan 2 student loans:

Income tax on bonus: £960 (20% of £4,800 after pension)
National Insurance: £400 (8% of £5,000)
Student loan: ~£450
Net bonus: ~£3,190

Run your exact figures through our salary calculator to see the precise deduction for your circumstances.

US Bonus Tax — Federal, Social Security, and State

US bonuses are taxed at your federal marginal bracket, plus Social Security and Medicare, plus state income tax (if applicable).

Federal income tax (2026, single filer) — your bonus is added to your annual income and taxed at the marginal rate:

10% up to $11,600
12% up to $47,150
22% up to $100,525
24% up to $191,950
And higher brackets beyond

Social Security (6.2%) and Medicare (1.45%) are deducted from the bonus unless you've already hit the Social Security wage base ($168,600 for 2026; see SSA tax rates).

State income tax varies widely: 0% in Texas, Florida, and Wyoming; up to 13% in California; and 6.5% in New York.

Example: Single filer, $65,000 salary + $5,000 bonus, no state tax:

Federal income tax: ~$1,100 (22% marginal bracket)
Social Security: $310 (6.2%)
Medicare: $73 (1.45%)
Net bonus (before state): ~$3,517

Add state income tax if applicable — this can range from $0 to $650 depending on your state.

Why Your Bonus Feels Smaller Than Expected

You're comparing average rate to marginal rate. Your salary feels fine because part of it sits in the 0% allowance band (UK) or the lowest tax brackets (US). A bonus added on top is taxed entirely at your current marginal rate, which is higher than your average. The 28% or 42% bite feels unfair because you're used to seeing 18% on your salary across the year — but both calculations are correct, and yes, your bonus genuinely is taxed more heavily.

Your employer withholds conservatively. Some employers (especially in the US) use "supplemental withholding" on bonuses — they withhold at 22% federal or even 37%, assuming the bonus is one-off income. This is often over-withholding, and you'll get a refund at tax time. In the UK, employers calculate based on your tax code, which is usually accurate unless you've hit a threshold mid-year.

You didn't budget for National Insurance or FICA. National Insurance is separate from income tax but still deducted from your pay. Many people only think of the 20% income tax component, then are surprised to see an additional 8% NI (28% total). FICA in the US works the same way — 6.2% Social Security + 1.45% Medicare is withheld before you see the federal income tax withholding.

You're near a tax threshold. If your bonus pushes you from basic rate to higher rate (£50,270 in the UK), part of the bonus is taxed at 40% instead of 20%. If you earn over £100,000, you lose your personal allowance at £1 per £2 earned, creating a 60% marginal rate on bonus income between £100,001–£125,140. This is a cliff, not a gradual transition — and a bonus arriving at the wrong time can cost you thousands in extra tax.

How to Maximize Your Bonus After Tax

Defer into a pension (UK). If your employer allows it, you can sacrifice a bonus into a pension before payday, avoiding income tax and NI entirely. A £5,000 bonus deferred into a pension costs you only £3,600 in net pay but lands £5,000 in your pension pot, growing tax-free. This only works if you haven't hit your annual pension allowance (£60,000/year as of 2026; check HMRC's rules).

Time bonuses across tax years if you're near a threshold. If you earn £48,000 and receive a £5,000 bonus in April, you're pushed to £53,000 (higher rate applies to part of it). If your employer can split the payment across tax years (£2,000 in April, £3,000 in July next year), you stay basic rate both years, saving tax on the second portion.

Invest your after-tax bonus in an ISA. Once the bonus lands in your account, you can invest up to £20,000/year into an ISA (tax-free growth). If you receive a £5,000 bonus, the full amount can sit in an ISA growing without income tax or capital gains tax. (ISA rules and limits)

Compare the full package, not just the bonus. A higher base salary and lower bonus might be worse for tax (salary is spread across bands, bonus is marginal). Stock options or company car benefits might be more tax-efficient in some cases. When negotiating salary, model the total package through a calculator rather than comparing gross bonuses on paper.

Frequently Asked Questions

Q: Is there a special lower tax rate on bonuses in the UK? No. Bonuses are taxed as ordinary income at your marginal rate. There's no special bonus tax rate, and no threshold that exempts bonuses. The only way to reduce tax on a bonus is to defer it into a pension (before the pay date) or to time it across tax years to avoid crossing a threshold.

Q: Why is my bonus taxed more heavily than my salary? It's not taxed more — it's taxed at the same marginal rate. But your salary is spread across 12 months, so part of it sits in the 0% personal allowance band. A bonus (typically paid in one lump sum) sits entirely in your marginal band, which is higher. That feels heavier because it is: your bonus marginal rate is higher than your average rate across the year.

Q: Can I avoid tax on a bonus? In the US, no — bonuses are taxable income. In the UK, you can defer a bonus into a pension if your employer allows it before payday, which avoids income tax and NI entirely. Otherwise, bonuses are taxable. There's no gift exemption or allowance.

Q: Should I negotiate a higher salary instead of a bonus to save tax? On tax alone, salary and bonuses are equivalent (both taxed at your marginal rate). However, salary is more "locked in" to your pay structure, while bonuses can vary. If you're near the £50,270 or £100,000 threshold in the UK, salary might be slightly more tax-efficient (the personal allowance is spread across 12 months rather than concentrated in one). Otherwise, negotiate on total take-home value, not the salary/bonus split.

Q: What if a bonus pushes me over £100,000 in the UK? You'll lose your personal allowance at a rate of £1 for every £2 earned between £100,001–£125,140, creating an effective 60% marginal rate on that portion. A £5,000 bonus at £98,000 income means £2,000 is taxed at basic rate (28%), and £3,000 is taxed at 60%. This is expensive. Consider deferring part of the bonus into a pension to bring your income back below £100,000.

Q: Will I get a tax refund on my bonus? Possibly. If your employer over-withholds (common in the US and when bonuses trigger supplemental withholding), you'll claim the refund when you file your tax return. In the UK, your employer adjusts your tax code in the following month, and you'll see the benefit on your next pay slip. Keep your payslip for the bonus month; it shows the exact withholding.