The £100k tax trap, defused in order
Between £100,000 and £125,140 the UK tax system hides its harshest band. This guide runs the five calculations every high earner needs — the 60% trap, the child benefit charge and the moves that legally cut your bill.
A £10,000 pay rise at £105k. How much do you keep?
60%
effective rate £100k–£125k
£60,000
HICBC starts
£1 for £2
allowance lost
Cross £100,000 and every £2 you earn quietly strips £1 of personal allowance, creating an effective 60% marginal rate up to £125,140 — a band most people never knew existed. Add the child benefit charge from £60,000 and a “good” pay rise can leave you barely better off. Each calculator below settles one piece — run them in order to see the trap and the way out.
The high earner path, step by step
Five calculations in the order they bite — spot the charges first, then use the levers that legally bring your taxable income back down.
Do you owe the child benefit charge?
If you or your partner earns over £60,000 and claims Child Benefit, the High Income Child Benefit Charge claws it back — fully gone by £80,000. It’s based on individual adjusted net income, not household, and is collected through Self Assessment. Check whether it applies before anything else.
Child Benefit Charge Calculator →How much is the personal allowance taper costing you?
Above £100,000, your £12,570 personal allowance tapers by £1 for every £2 earned, fully gone by £125,140. That creates an effective 60% rate on income in that band. Seeing the exact cost is the first step to deciding how much to divert into a pension.
Allowance Taper Calculator →How much should you salary sacrifice?
Salary sacrifice into a pension reduces your adjusted net income, which can pull you back below £100,000 — escaping the 60% trap and restoring your allowance — and below £60,000 to avoid the child benefit charge. It’s the single most powerful legal lever. Work out how much to sacrifice.
Salary Sacrifice Calculator →How are your dividends taxed on top?
If you have dividend income alongside a high salary, it stacks at the top of your income, taxed at higher (35.75%) or additional (39.35%) rates with only a £500 allowance. It also counts toward the £100k and £125,140 thresholds, so it can deepen the trap. Factor it in.
Dividend Tax Calculator →Can you claim the marriage allowance?
If one partner earns below the personal allowance and the other is a basic-rate taxpayer, marriage allowance transfers part of the unused allowance. It doesn’t help once you’re a higher-rate payer, but it’s worth checking in households with uneven incomes. A small, often-missed saving.
Marriage Allowance Calculator →Why the order matters
The charges come first because you can’t manage what you can’t see. Most people hit the 60% band or the child benefit charge without realising — a bonus or pay rise tips them over, and the damage only shows up at tax-year end. Quantifying the cost is what makes the case for acting.
Salary sacrifice comes before the dividend and marriage-allowance steps because it’s the lever that moves the others: by lowering your adjusted net income it can restore the personal allowance and remove the child benefit charge in one move. Fix the big trap first, then tidy up the smaller pieces around it.
The 60% tax trap, band by band
These are the effective marginal rates a high earner faces. The 60% band between £100,000 and £125,140 is the one that catches people out.
| Income band | Effective marginal rate |
|---|---|
| £50,271 – £100,000 | 40% (higher rate) |
| £100,000 – £125,140 | ~60% (taper) |
| Over £125,140 | 45% (additional rate) |
Including National Insurance, the £100k–£125,140 band can reach around 62%. The taper applies to adjusted net income, which pension contributions and Gift Aid reduce — which is exactly why salary sacrifice is so effective here. Model your own position with the salary sacrifice calculator.
Ready to run your own numbers?
Begin by checking the child benefit charge and the taper — the charges that quietly bite — then work down the path one calculator at a time.
A high earner’s path, worked through
One realistic example, run through the whole sequence, to show how the steps connect in practice.
- Child benefit charge. At £110,000, James is well into the HICBC zone (£60k–£80k), so the benefit is fully clawed back through Self Assessment.
- The 60% band. His income sits in the £100k–£125,140 band, where the personal allowance tapers — an effective 60% marginal rate.
- Salary sacrifice. He sacrifices £10,000 into his pension, dropping adjusted net income to £100,000 — escaping the taper and restoring child benefit in one move.
- Dividends. He checks that a small dividend portfolio doesn’t tip him back over the thresholds.
- Marriage allowance. Not applicable here — his wife is also a taxpayer — so he skips it.
The takeaway: a £10,000 pay rise at this level can be worth almost nothing after the 60% taper and lost child benefit. Diagnosing the charges first showed James that sacrificing into a pension beat taking the cash — the lever moved everything at once.
Five mistakes high earners make
The errors that recur among UK high earners — and the ones that cost the most.
Not realising the 60% band exists
Between £100,000 and £125,140 the tapering personal allowance creates an effective 60% rate (62% with NI). Many discover it only at tax-year end, after a bonus or rise. Spotting it early lets you plan.
Cost: ~60p lost per extra £1 Fix: model the taper before a riseSpending money to get under £100k
Don’t panic-spend to dodge the trap — that just leaves you poorer. Pension contributions and Gift Aid reduce adjusted net income while preserving your wealth. Use the right lever, not blunt spending.
Cost: wealth simply lost Fix: use pension/Gift Aid, not spendingMissing that the child benefit charge is individual
HICBC is based on the higher earner’s individual income, not household. A couple both on £55k keep it; one earner on £80k loses it all. Knowing this shapes who should sacrifice salary.
Cost: an avoidable clawback Fix: plan around individual incomeForgetting dividends count toward the thresholds
Dividend income stacks toward the £100k and £125,140 thresholds, so it can push you into the 60% band even if salary alone wouldn’t. Factor all income, not just PAYE.
Cost: an unexpected 60% hit Fix: include dividends in the totalTaking a pay rise as cash without checking the maths
In the 60% band you keep only ~40p of each extra £1 — less if child benefit goes too. Many high earners sacrifice a rise straight into a pension rather than take so little of it as cash.
Cost: keeping little of a rise Fix: consider sacrificing the riseHigh earner tax questions, answered
What is the 60% tax trap?
How can I avoid the 60% tax trap?
When does the High Income Child Benefit Charge apply?
Does salary sacrifice reduce the child benefit charge?
How are dividends taxed for high earners?
Is the marriage allowance worth claiming?
Does a pay rise above £100k ever leave me worse off?
Other Calclens guides & tools
How this guide is built
The sequence follows how the high-income charges actually bite — identifying the child benefit charge and the personal allowance taper, then applying the levers that reduce adjusted net income — the order a tax adviser would use to plan around them.
Every calculator linked here is a free Calclens tool with its own methodology. The £100,000 taper, the £60,000–£80,000 child benefit charge, dividend rates and salary sacrifice follow current HMRC and GOV.UK guidance; the individual calculator pages carry the detailed figures and sources.
Definitions and sources: methodology · sources.
Not tax or financial advice. This guide is for general information and links to calculators that produce estimates. High-income tax planning depends on your circumstances — confirm figures with a qualified accountant or financial adviser before acting.