The £100k Tax Trap: How the 60% Rate Actually Works (And 4 Ways to Escape It)

If you’re earning between roughly £95,000 and £130,000 in the UK, the tax system has a nasty surprise waiting for you — one HR and payroll departments almost never explain. Every £1 you earn in the £100,000–£125,140 slice is taxed at an effective marginal rate of 60%, not the 40% higher-rate band you’d expect. On a £5,000 pay rise, you can take home less than £2,000. On some bonus structures, you can take home less than nothing.

This isn’t a tax loophole. It isn’t a gotcha. It’s an intentional feature of the UK tax code called the tapered Personal Allowance, and it has been in place since April 2010. Yet it’s the single most misunderstood mechanism in UK personal finance, and it costs people who don’t know how to work around it several thousand pounds a year in tax they didn’t need to pay.

This is the deep guide: what the trap actually is, exactly how the 60% number comes out of the maths, why it can silently push your marginal rate even higher when you have kids, and — most importantly — the four legitimate ways to escape it. All the numbers below are 2024/25 rates.

📥 Companion resource: we’ve packaged the practical escape moves — 12 of them — into a free PDF playbook with worked examples and a self-audit checklist. Download the £100k Trap Escape Playbook (PDF, 105 KB, no signup).

What the £100k trap actually is

Every UK taxpayer gets a Personal Allowance — the first £12,570 of income you can earn without paying any Income Tax on it. It’s the tax code’s most valuable single allowance because it comes off the top of your marginal rate: for a higher-rate taxpayer it’s worth up to £5,028 a year (£12,570 × 40%).

But at £100,000 of “adjusted net income”, the government starts to withdraw it. The rule is simple and mechanical:

For every £2 you earn over £100,000, you lose £1 of your Personal Allowance.

At £125,140 (that is, £100,000 + 2 × £12,570), you’ve lost the entire Personal Allowance. From that point on, you’re back to a normal-looking marginal rate.

So the trap has three sides:

On the £25,140 slice between £100k and £125,140, you pay 40% Income Tax on the income itself, plus
You also lose 50 pence of tax-free allowance for every £1 earned, and that lost allowance would have shielded income from 40% tax, so you pay an additional 20% (0.5 × 40%) on the same slice, plus
You still pay 2% National Insurance on it (Class 1 employee NI drops from 8% to 2% above the Upper Earnings Limit of £50,270, so most people in this band are in the 2% NI zone).

That’s an effective marginal rate of 62% — usually rounded to 60% in shorthand because the NI portion is technically a separate levy.

Below is the same thing as a table. This is your marginal rate on the next pound you earn:

Band	Income slice	Income tax	NI	Personal Allowance loss	Effective marginal rate
Personal Allowance	£0 – £12,570	0%	0%/8%	–	0% – 8%
Basic rate	£12,570 – £50,270	20%	8%	–	28%
Higher rate	£50,270 – £100,000	40%	2%	–	42%
The trap	£100,000 – £125,140	40%	2%	+20%	62%
Additional rate	£125,140 – £150,000	45%	2%	–	47%
Additional rate	£150,000+	45%	2%	–	47%

Look at what that does: your marginal rate goes 42% → 62% → 47% and then stays at 47%. There is a slice of income where a lower earner pays a higher marginal rate than a higher earner. That is what’s meant by “the trap” — you are worse off, pound-for-pound, than someone earning £150k.

What it looks like on a £5,000 pay rise

Let’s take a concrete example. You currently earn £100,000. Your employer offers you a £5,000 pay rise. Sounds great. Let’s do the actual maths.

Before the pay rise, your Personal Allowance is intact at £12,570.

After the pay rise, adjusted income is £105,000. You’ve gone £5,000 over £100k, so you lose £5,000 ÷ 2 = £2,500 of Personal Allowance. Your new Personal Allowance is £10,070.

The tax cost of the pay rise breaks down like this:

Income Tax on £5,000 at 40% = £2,000
Lost Personal Allowance of £2,500 × 40% = £1,000 (this £2,500 was previously tax-free; now it’s taxed at 40%)
NI on £5,000 at 2% = £100

Total additional deductions: £3,100. You keep £1,900 out of £5,000 — a 38% take-home rate.

That’s the 62% marginal rate showing up in the wild. It gets worse if you have young children and were claiming Tax-Free Childcare (worth up to £2,000/child/year) — Tax-Free Childcare is withdrawn entirely at £100,000 of adjusted income. Cross the line, lose it. Cliff edge, not taper.

For families with two under-3s in nursery, this can push the effective marginal rate on that £5,000 pay rise above 100%. Yes, above 100%. You genuinely take home less money by earning more. This isn’t an exaggeration — it’s why parents at HR conversations sometimes say “please don’t promote me this year.”

You can plug your own numbers into our UK income tax calculator and see the effective rate on the £100k–£125,140 band.

What “adjusted net income” actually means

The reason the trap is escapable at all is that the £100,000 threshold isn’t checked against your gross salary. It’s checked against your adjusted net income — HMRC’s term for total taxable income minus a few specific deductions. Those deductions are the escape hatches.

Adjusted net income is, roughly:

Gross salary and bonuses
Plus taxable benefits (company car, private medical insurance, etc.)
Plus dividends, savings interest, rental income
Plus any other taxable income
Minus grossed-up pension contributions you made yourself
Minus grossed-up Gift Aid donations
Minus trading losses

The two big levers — pension and Gift Aid — get “grossed up” because HMRC treats a £4,000 personal pension contribution as if it were an £5,000 gross contribution (the pension provider claims back 20% basic-rate tax on your behalf, adding £1,000 to the pot). So the £4,000 you pay in reduces your adjusted net income by £5,000, not £4,000.

That grossing-up is what makes the escape maths so favourable.

Escape route 1: Salary sacrifice into pension

This is the simplest and most powerful escape. Instead of receiving £5,000 as extra salary, you agree with your employer to take £5,000 less salary and receive £5,000 additional pension contribution instead. Because the money never reaches your pay packet, it never counts towards adjusted net income at all.

The maths:

You give up £5,000 gross salary.
If you would have taken that home at the 62% marginal rate, you were only going to keep £1,900 of it.
All £5,000 goes into your pension, plus your employer typically adds back the 13.8% employer NI they saved by not paying you that £5,000 as salary. Many employers reroute that back into your pension (worth checking — some pocket it).
You’ve converted £1,900 of after-tax money into ~£5,690 of pension money. That’s a ~200% instant return.

Salary sacrifice is available through your employer only. You can’t do it yourself with a personal pension or SIPP. Ask HR: “Do we offer salary sacrifice for pension contributions?” If the answer is no, it’s often the single most valuable benefit HR can implement — and adding it costs the company nothing because they save NI on top.

Our salary sacrifice calculator will show you the exact take-home impact for your salary and pension %, including the £100k trap band.

Escape route 2: Personal pension top-up (SIPP or workplace)

If salary sacrifice isn’t available at your employer, the second-best route is a personal pension contribution — either into your workplace pension via extra AVCs (Additional Voluntary Contributions) or into a SIPP you open yourself.

The mechanics are slightly less efficient than salary sacrifice because you contribute out of already-taxed take-home pay, then reclaim the tax through your tax return. But the impact on adjusted net income is the same.

Example: you earn £110,000 and want to get back under £100,000.

Contribute £8,000 net into a SIPP.
Your provider adds £2,000 (20% basic-rate tax relief) automatically. Your gross contribution is £10,000.
Your adjusted net income drops from £110,000 to £100,000. You reclaim the entire tapered Personal Allowance.
On your tax return (or via a P810 letter), you claim an additional £2,000 of higher-rate relief (20% of £10,000) as a rebate.
On the £10,000 that was previously taxed at 60% marginal, you’re now getting effective relief of 60%, meaning it cost you £4,000 to put £10,000 into a pension.

Combine the pension pot gain, the reclaimed Personal Allowance, and the higher-rate relief and this is arguably the highest ROI move in the entire UK tax code. Nothing else, legally, comes close.

Our SIPP tax relief calculator does this maths for you — plug in your salary and desired contribution and it shows the true net cost.

Escape route 3: Gift Aid donations

Gift Aid donations to registered UK charities work identically to pension contributions for adjusted-net-income purposes. Every £80 you donate becomes a £100 gross contribution (the charity claims the £20 basic-rate tax back). Higher-rate relief goes to you via the tax return.

This one is worth flagging because most people don’t realise donations shrink the 60% trap:

You donate £4,000 net (£5,000 gross with Gift Aid) to charity.
If you were earning £105,000, this drops you back to £100,000 adjusted net income.
Full Personal Allowance restored → £5,028 in tax saved.
Plus higher-rate relief on the £5,000 gross donation → £1,000 rebate.
Total effective cost of the £5,000 donation: £2,972. The charity gets £5,000, you keep the Personal Allowance, and you’ve turned a 60% marginal into a very tax-efficient philanthropy.

If you were going to donate anyway, doing it strategically to stay under £100k adjusted income massively multiplies the benefit.

Escape route 4: Bonus timing and Bed & ISA

For people whose income is variable — bonuses, RSUs vesting, self-employed with peaky invoicing — bonus timing can be an entire strategy on its own.

Two techniques worth knowing:

Bonus sacrifice — some employers let you divert some or all of a bonus into pension before it hits payroll. Same NI advantage as salary sacrifice, but applied to a single lump. If you’re expecting a bonus that will push you into the trap, ask HR whether bonus sacrifice is an option and give the instruction well before payroll cut-off. Many people find out about this the day after the bonus lands, which is too late.

Timing across tax years — if you can defer a bonus payment or invoice date past 5 April, you can smooth income across two tax years. This is legitimate as long as the deferral is genuine (i.e., the money isn’t already owed to you and available to draw). Contractors on their own PSCs have the most flexibility here; PAYE employees usually don’t.

Bed & ISA — if you have gains sitting in a general investment account that will push your adjusted net income up (because dividends and interest count), moving them into an ISA shelters future income from adjusted net income calculations forever. Every UK adult has a £20,000 ISA allowance per tax year. Use our ISA vs GIA calculator to see the compounding tax drag of not doing this.

When it’s NOT worth escaping

The £100k trap is worst if you’re deep inside it (say £110,000–£120,000) and you have young children losing Tax-Free Childcare. Escaping is close to a no-brainer there.

But the escape isn’t free. Money in pension is locked up until age 57 (rising to 58 from 2028). If you need the cash for a house deposit, a business, or an emergency, “saving £3,100 in tax by locking £5,000 in pension until age 57” might not be the right trade.

The clearest cases for pension-based escape are:

You’re already going to save that money for retirement anyway → no lock-up cost, big tax win.
You’re a higher earner with a young family losing Tax-Free Childcare or Free Childcare Hours at £100k → the escape recovers benefits worth far more than the pension lock-up.
You have a lumpy income year and want to smooth the marginal rate → SIPP top-ups are perfect for this.

The unclear cases:

You have short-term cash needs (house deposit, wedding, business).
You’re already at or near the annual pension allowance (£60,000 with tapering above £260,000).
You’ve maxed the Lifetime Allowance’s replacement thresholds and are worried about future tax on pension crystallisation.

If in doubt, talk to a fee-only adviser. But don’t skip this because you assumed it was too complicated. The maths are the maths.

The one-page summary

The £100k trap is real and creates a 62% effective marginal rate on the £100,000–£125,140 income slice.
It bites even harder for families with young children (loss of Tax-Free Childcare at £100k adjusted income).
The threshold is against adjusted net income, not gross salary. That’s your escape.
Four routes reduce adjusted net income: salary sacrifice (best), personal pension top-ups (nearly as good), Gift Aid (great if you’d donate anyway), and bonus/timing plays (situational).
Every £1 you drop your adjusted income from £120k back to £100k is worth roughly 62p in tax saved, plus reclaimed benefits.
This is legitimate use of the tax code, not aggressive avoidance. HMRC actively expects people to do this — the reliefs are on the CT600 and SA100 for exactly this reason.

Frequently asked questions

Does the £100k threshold move with inflation? No. It’s been frozen at £100,000 since April 2010, and the £125,140 top of the taper was set when the additional-rate threshold was moved in April 2023. Fiscal drag means every year of wage growth pulls more people into the trap. In 2010 about 250,000 people were affected; today it’s over a million.

I’m in Scotland — does this still apply? Yes. Personal Allowance and its taper are UK-wide rules set by Westminster. Scottish rates and bands apply to Income Tax itself, but the £100k taper is identical. The effective marginal rate is slightly higher in Scotland (around 63% due to different band rates). See our Scottish take-home calculator for the exact split.

What counts as “adjusted net income” for a self-employed person? The same rules apply, using taxable trading profit (after allowable expenses and capital allowances) as the starting point. Pension contributions still get grossed up. If you’re a company director paying yourself via salary + dividends, both count towards adjusted net income and both can be shielded by pension contributions.

Can I escape the trap by taking a company car or salary in RSUs? No. Taxable benefits and RSUs vesting both count as income for adjusted net income. Non-cash compensation doesn’t dodge the trap. This is a common misconception — people think “I’ll take the medical insurance instead of a raise” and are surprised when the P11D BiK still counts. Our total compensation calculator helps you see the true after-tax value of each package component.

What about employer pension contributions? Employer contributions (including salary sacrifice contributions the employer routes to your pension) are the cleanest form of the escape. They never count as your income at any point. If you can push £5,000 of gross pay into an employer contribution, £5,000 exits your adjusted net income immediately.

Is there a downside beyond the pension lock-up? The pension lifetime allowance was abolished in April 2024 and replaced by lump-sum-only limits, so there’s less risk of “over-saving” than there used to be. The main downside is annual allowance tapering: if your adjusted income exceeds £260,000, your £60,000 annual pension allowance starts to taper down to as low as £10,000. Above £360,000 you’re stuck at £10,000/year. High earners planning aggressive top-ups should check this ceiling first.

Should I bother if I’m at £101k? Absolutely — even £1,000 of pension contribution recovers £2,000 of Personal Allowance × 40% = £800 of tax saved, on a £1,000 contribution that would have cost you £380 in take-home money. That’s an instant 110%+ return on the extra £620 the pension gained. The lower into the trap you are, the higher the effective return on the escape.

UK Income Tax calculator — see the full marginal rate on each band including the trap.
Salary sacrifice calculator — model exactly how much a pension sacrifice returns.
SIPP tax relief calculator — for personal contributions outside salary sacrifice.
Total compensation calculator — compare job offers correctly with the £100k trap band selected.
UK take-home pay calculator — full breakdown by band, all rates included.

This article is educational, not personal advice. Everyone’s circumstances differ. For decisions involving large sums, a fee-only Chartered Financial Planner is worth their fee many times over.