About the UK Income Tax Calculator
Income tax and National Insurance on employment income, with every threshold exposed as an input so the calculator can be corrected when they move rather than going quietly stale.
The reason to build this rather than use a generic take-home calculator is one feature of the UK system that almost nobody is told about, that appears in no table of rates, and that nothing on a payslip reveals:
Between £100,000 and £125,140, the marginal rate is 60%.
How to Use the UK Income Tax Calculator
Enter your gross annual salary and any pension contribution as a percentage.
The thresholds default to the 2025/26 figures for England, Wales and Northern Ireland. Check them against the current tax year — they move most years, and a hard-coded figure becomes wrong without anything appearing to break.
Scotland sets its own income tax bands. This models the rest of the UK. You can enter Scottish thresholds manually; National Insurance is UK-wide either way.
Step-by-Step Example
£60,000, no pension contribution.
Personal allowance: 12,570
Taxable income: 47,430
37,700 at 20%: 7,540.00
9,730 at 40%: 3,892.00
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Income tax: 11,432.00
National Insurance: 3,210.60
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Take-home: 45,357.40 (3,779.78 a month)Effective rate 24.4%. Marginal rate 42% — which is the number that governs any overtime, bonus or rise.
The 60% Trap
The personal allowance is withdrawn at £1 for every £2 of income above £100,000.
So earning one extra pound does two things at once: it adds a pound of taxable income, and it removes fifty pence of allowance. That creates £1.50 of newly taxable income, taxed at 40%:
£1.50 × 40% = 60p of income tax per extra £1
plus 2% National Insurance
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Marginal rate: 62%And here is what makes it genuinely perverse — the rate falls once you are through it:
| Income | Marginal rate |
|---|---|
| £30,000 | 28% |
| £60,000 | 42% |
| £101,000 | 62% |
| £124,000 | 62% |
| £130,000 | 47% |
Someone on £110,000 keeps 38p of their next pound. Someone on £200,000 keeps 53p. The band between £100,000 and £125,140 is the most heavily taxed income in the UK system, and it exists as a side effect of a taper rather than as a decision anyone announced.
The allowance runs out at exactly £125,140 because £100,000 + (2 × £12,570) is £125,140. That is the whole derivation of that odd-looking number.
Escaping It
A pension contribution reduces the income the taper is measured against — so it buys back allowance as well as avoiding tax on the contribution itself.
On £110,000, contributing £10,000 takes you back to £100,000 and restores the entire personal allowance. Inside the band, every £1 contributed costs about 38p of take-home.
There is no other pension contribution available to anyone at any income that is this efficient. If you are in this band and not contributing, it is worth understanding exactly why before continuing.
Other routes that reduce the income the taper sees include salary sacrifice and Gift Aid donations. All of them work on the same principle: the taper measures adjusted net income, so anything that reduces that figure works twice.
Effective Against Marginal
Two rates, answering different questions, and routinely confused.
Effective rate is total tax and National Insurance divided by gross salary. It describes your pay as a whole. At £60,000 it is 24.4%.
Marginal rate is what applies to the next pound. At £60,000 it is 42% — well over half again.
If you are deciding whether overtime is worth it, or what a bonus will net, the marginal rate is the only relevant one. Quoting yourself the effective rate will make extra work look considerably better than it is.
What Is Not Included
Worth being explicit, because several of these interact with the taper:
- Student loan repayments, which are a further deduction above a threshold.
- The High Income Child Benefit Charge, which can push an effective marginal
rate well above 60% for a household with children.
- Salary sacrifice arrangements, which change the calculation upstream.
- Taxable benefits in kind, which raise the income the taper measures.
- Any income that is not employment income — dividends, savings interest,
rental and self-employment all have their own treatment.
Understanding Your Result
Take-home is annual and monthly.
Tax and National Insurance separates the two, which payslips often blur.
Personal allowance shows whether the taper has taken any of it, and how much.
Effective and marginal gives both rates and says which governs what.
Worth knowing flags the 60% band, the pension case, or the Scotland caveat.
When Should You Use This Calculator?
Whenever income is near £100,000. This is the case it exists for.
Before accepting a rise that crosses £100,000. A £5,000 rise into the band nets about £1,900.
To decide a pension contribution. The cost per pound is the deciding figure.
To check a payslip. If take-home does not reconcile, something is worth asking about.
Common Mistakes
Not knowing the 60% band exists. It is in no rate table and on no payslip.
Assuming the top rate is the highest rate. 47% above £125,140 is lower than 62% below it.
Using the effective rate to judge extra work. Extra work is marginal.
Declining a pension contribution inside the taper. It costs about 38p in the pound there.
Using last year's thresholds. They move, and the calculator lets you correct them.
Applying these figures in Scotland. The bands differ.
Thresholds and rates change every tax year and vary within the UK. Every figure here is an estimate for planning, not tax advice.