Is my payslip right?
Enter the figures from one payslip and we'll show the tax, National Insurance and student loan we'd expect, how that compares with what came off, and the likely reason for any gap.
Your answer
Enter how often you're paid, your pay before deductions and your tax code to check your payslip.
About this calculator
For anyone paid through payroll who wants to check one payslip: after starting a new job, a new tax code, a pay change, or when the tax just looks wrong.
Works with every tax code, emergency codes (W1, M1, X), monthly, weekly and 4-weekly pay, the common National Insurance letters, student loans and the three ways of paying into a pension.
What happens to your answers
We don’t keep them. Your answers go to our server to do the sums and aren’t stored or logged. If you copy a link to your answers, they’re in the link itself, so only share it with people you trust.
How it’s worked out
We work out the tax the way HMRC's payroll tables do. Your code gives you a slice of tax-free pay each payday (1257L gives £1,048.26 a month). Most codes count the whole tax year so far: tax due on all your pay to date, less the tax you've already paid. That's why one payslip can take extra tax, or give some back, after a change. Codes ending in W1, M1 or X tax each payday on its own.
National Insurance is 8% of your pay between £1,048 and £4,189 a month (£242 and £967 a week), and 2% above, worked out on each payday on its own. If you're over State Pension age you pay none. Student loans take 9% of pay over your plan's threshold, in whole pounds.
Then we compare with what your payslip shows. A difference of a few pence is normal rounding. Anything bigger usually means a different tax code, earlier pay being caught up, or pay we don't know about.
Worked example
Your payslip shows £209.80 more tax than we'd expect this payday.
2026/27 tax year · Monthly pay · code 1257L, steady pay · letter A · 5% pension before tax · no student loan
| Your pay before anything is taken off (monthly) | £3,000.00 |
|---|---|
| Pension taken before tax (5%) | − £150.00 |
| Pay that's taxed this payday | £2,850.00 |
| 1257L: tax-free pay for one month is (1257 × £10 + £9) ÷ 12, rounded up to the penny, in blocks of 500 | £1,048.26 |
| Income tax at 1257L (steady pay) | − £360.20 |
| National Insurance: 8% of pay from £1,048.00 to £4,189.00, 2% above | − £156.16 |
| Take-home pay we'd expect | £2,333.64 |
| Tax on your payslip: £570.00 | + £209.80 |
| National Insurance on your payslip: £156.16 | No difference |
Worked out using HMRC's published rates for the 2026/27 tax year (6 April 2026 to 5 April 2027), on a yearly basis.
Questions people ask
Why has my tax gone up or down this month?
Most tax codes count the whole tax year so far. If your code changes, or your pay goes up or down, the next payslip puts the year right in one go: it can take extra tax, or give tax back. Add the 'to date' figures from your payslip and we'll show whether that explains it.
My tax looks wrong. What should I do?
Ask your payroll team first: they can tell you which tax code and National Insurance letter they're using. Check your code in the HMRC app or your personal tax account too. If your code is wrong, update your details there and HMRC tells your employer. If payroll and your code both look right and you still think it's wrong, contact HMRC.
I'm over State Pension age. Why is National Insurance still coming off?
You stop paying employee National Insurance once you reach State Pension age, but your employer needs proof, such as your passport or birth certificate. Show them and they should switch you to letter C and refund anything taken since.
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