Most employees receive a payslip each month and file it away without reading it carefully. Which is understandable: the number that matters, the take-home amount landing in the bank, is the one most people focus on. But payslip errors do occur, and they are not always immediately obvious. Tax code mistakes, incorrect hourly rates, missing overtime, or the wrong pension contribution can all result in you being paid less than you should be.
Understanding what each section of a payslip means makes it possible to catch these things before they accumulate.
Gross pay
This is your total earnings before any deductions. For salaried employees, it should match your annual salary divided by twelve. If you are hourly paid, it should reflect your contracted hours plus any overtime or additional hours at the correct rate. Check this figure first, because all the deductions below come out of it, and if it is wrong, everything else will be wrong too.
Income tax
The amount of income tax deducted depends on your tax code. Your tax code is shown on the payslip and tells HMRC how much of your income is tax-free. The most common code is 1257L, which means your first £12,570 of annual income is tax-free (the standard personal allowance for the 2025 to 2026 tax year). If your code is different, it may be because of company benefits, multiple jobs, or a previous underpayment. If it looks unusual, checking it with HMRC via the Government Gateway is worth doing.
National Insurance
National Insurance contributions are calculated as a percentage of earnings above a weekly or monthly threshold. The rates have changed several times in recent years, so checking the HMRC website for the current rates and thresholds is the most reliable way to verify your NI deduction rather than relying on memory.
Pension contributions
If you are automatically enrolled in a workplace pension, your payslip will show your contribution and usually your employer's contribution separately. The minimum for employees is five per cent of qualifying earnings, with employers contributing at least three per cent. Check that both figures appear and match what your employer communicated. Some employers contribute more than the minimum, which should be visible on the payslip.
What to do if something looks wrong
Raise it with your HR or payroll team in writing. Be specific about what you believe is incorrect and why. Most payroll errors are genuine mistakes and can be corrected in the following month's pay run. If you believe you have been consistently underpaid and the employer does not correct it, Citizens Advice can explain your options, which may include a formal claim through ACAS or an employment tribunal.
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Ask Fin provides general guidance only, not regulated financial or employment advice. For specific employment matters, contact ACAS or Citizens Advice.