Gross pay is the headline number on your contract — but it is not the money that reaches your bank. Here is the difference that matters.
When a job advert says "£35,000 a year", that is gross pay — the amount before the taxman, the National Insurance system and your pension all take their slice. Understanding gross pay, and why it is always bigger than the money you actually receive, is the foundation of reading any payslip.
The relationship is straightforward: gross pay minus deductions equals net pay. The deductions for an employee in 2025/26 typically include:
Because these are calculated on your gross pay, the gross figure drives everything else on the payslip. Crucially, the deductions are not applied as a single flat percentage. Income Tax only bites on the slice of gross pay above your Personal Allowance, and then steps up through the bands; National Insurance has its own separate thresholds. This is why your effective deduction rate rises as you earn more, and why a pay rise never increases your take-home pay by the full gross amount.
It also matters that some deductions reduce your taxable gross pay before tax is worked out. Pension contributions made under salary sacrifice or a net pay arrangement, for example, come off the top, lowering the gross figure that Income Tax and sometimes National Insurance are charged on. So the gross pay on your contract and the gross pay used to calculate your tax are not always identical.
Consider Tom, who has an annual salary of £35,000 and is paid monthly on tax code 1257L.
His annual deductions work out roughly as:
| Deduction | Annual amount |
|---|---|
| Income Tax (20% on £35,000 − £12,570 = £22,430) | £4,486 |
| National Insurance (8% on £35,000 − £12,570) | £1,794 |
| Pension (5% employee on qualifying earnings) | ≈ £1,121 |
| Total deductions | ≈ £7,401 |
That leaves annual net pay of around £27,599, or roughly £2,300 a month. The gross figure of £2,916.67 a month is what the contract promises; the £2,300 is what Tom can actually spend. In other words, around 21% of Tom's gross pay never reaches his account, and that proportion would climb if he earned enough to cross the £50,270 higher-rate threshold, where the next slice of income is taxed at 40%. Run your own numbers with the salary calculator.
Gross pay is the figure lenders, landlords and HMRC care about. Mortgage affordability is assessed on gross income, pension contributions are calculated as a percentage of it, and your Income Tax band is determined by your total gross income across the year. It also matters for benefits and allowances that taper away above certain thresholds, such as the High Income Child Benefit Charge, which now applies between £60,000 and £80,000 of income, and the gradual loss of the Personal Allowance above £100,000.
This is why two people can have very different financial lives on paper despite similar take-home pay. Someone with a high gross salary but heavy pension contributions may take home the same as a lower earner, yet appear far more creditworthy to a mortgage lender and have a much larger retirement pot building in the background. Understanding your gross pay, and how each deduction reshapes it, is the starting point for almost every financial decision, from negotiating a salary to claiming a tax relief.
Gross pay is the promise; net pay is the reality. The gap between them is the tax system at work.
For sole traders there is no employer calculating gross and net pay. Instead, your equivalent of gross pay is your total business income (turnover), from which you deduct allowable business expenses to reach your taxable profit. Income Tax and Class 4 National Insurance are then charged on that profit through Self Assessment, and from April 2026 reported through Making Tax Digital quarterly updates. The principle is the same: tax is applied to a gross figure, and what you keep is the net result.
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