Example: a payslip that matches
Replace the example with the figures from your payslip. Paid 25 September 2026: tax year 2026/27, month 6. Tax assumes the same pay every payday since April, so it can differ by up to £1.
| Deduction | On payslip | Expected |
|---|---|---|
| Income TaxMatches | £360.20 | £360.20 |
| National InsuranceMatches | £144.16 | £144.16 |
| Student loan (Plan 2)Matches | £36.00 | £36.00 |
- 1257L: £1,048.26 tax-free pay a month.
With these deductions and your pension, take-home before any other deductions is £2,309.64.
How the check works
Income Tax is worked out the way payroll software must, from HMRC’s specification: your code’s tax-free pay, taxable pay rounded down to whole pounds, and the tax bands shared out over the year. National Insurance and student loans are worked out on each payday’s pay alone, with HMRC’s thresholds for the week or month. It checks the deductions set by law; anything else on your payslip, such as union fees or a cycle scheme, is up to your employer.
Frequently asked questions
How do I check my payslip is right?
Start with the tax code, which your employer gets from HMRC. Then compare each deduction with what the rules give for your pay: Income Tax on that code, National Insurance and any student loan. The checker does this for one payslip and suggests the likely reason for any difference.
Why has my tax changed when my pay hasn’t?
Most codes work cumulatively: each payday your employer works out the tax due on your pay for the year so far and takes the difference. A new code from HMRC is applied back to April, so one payday can include a refund or extra tax. Tax also changes when a code moves to or from a week 1/month 1 basis.
What do W1, M1 or X after my tax code mean?
They mean a week 1 or month 1 basis: each payday is taxed on its own, using only that week’s or month’s share of your tax-free pay. It is often used as an emergency code in a new job. You don’t overpay on a steady wage, but unused tax-free pay from earlier in the year isn’t given back until HMRC sends your employer a cumulative code.
How is National Insurance worked out on a payslip?
On each payday’s pay alone, with nothing carried over. In 2026/27 employees pay 8% on pay between £242 and £967 a week (£1,048 and £4,189 a month) and 2% above. So a bonus month pays more National Insurance, and a month below the threshold pays none.
How is student loan worked out on a payslip?
It is 9% of pay above your plan’s weekly or monthly threshold, rounded down to whole pounds; for Plan 2 in 2026/27 that is £565.09 a week or £2,448.75 a month. A fortnight or four weeks is worked out on the average week. It uses the same pay as National Insurance, so a salary sacrifice pension lowers it. The Postgraduate Loan is 6% above £21,000 a year.
Is what I enter stored anywhere?
No. The check runs in your browser. Nothing you enter is saved, sent or added to the page address.
Related calculators & guides
Sources — official UK figures
- HMRC — Specification for PAYE tax table routines (payroll technical specifications) ↗
- HMRC — Employer further guide to PAYE and National Insurance contributions (CWG2) ↗
- HMRC — Student and Postgraduate Loan deduction tables (SL3) ↗
- HMRC — Rates and thresholds for employers 2026 to 2027 ↗
Last reviewed June 2026 against official rates · How we calculate →
A check of one payslip against HMRC’s rules for the tax years 2024/25 to 2026/27. It can’t see your employer’s records, so a payslip can be right for reasons it doesn’t know about, such as a code changed during the year or pay from an earlier job. For your tax code and what HMRC holds, use your personal tax account or the HMRC app. Not financial advice.