How to Use a Salary Calculator (and Why Everyone Should)
By calculatemysalary.co.uk Editorial Team
A salary calculator shows you your actual take-home pay and helps you budget accurately.
Your gross salary is not your salary. That £35,000 on your contract? After income tax and National Insurance, you're taking home about £2,393 a month. Add a 5% pension contribution and it drops to £2,248. That's a gap of nearly £670 every month between what you earn and what hits your bank account.
A salary calculator works it out in seconds.
What gets deducted from your pay
Four things come off your gross salary before you see a penny.
Income tax is the big one. In 2025/26, you get £12,570 tax-free (your personal allowance). After that, you pay 20% on earnings up to £50,270, then 40% up to £125,140, and 45% on everything above.
National Insurance takes another bite. Employees pay 8% on earnings between £12,570 and £50,270 a year, then 2% on anything above.
Pension contributions vary by employer. If you're auto-enrolled, you're likely paying 5% of qualifying earnings. Some employers match more, some don't.
Student loan repayments depend on your plan. Plan 2 takes 9% of everything you earn above £27,295.
Worked example: £35,000 salary
Here's what a £35,000 salary actually looks like in 2025/26:
| Deduction | Annual | Monthly |
|---|---|---|
| Gross salary | £35,000 | £2,917 |
| Income tax | £4,486 | £374 |
| National Insurance | £1,794 | £150 |
| Pension (5%) | £1,750 | £146 |
| Take-home pay | £26,970 | £2,248 |
Those numbers shift if you're on a different tax code, paying off a student loan, or making salary sacrifice contributions. That's exactly why a calculator is useful. Plug in your actual details and get your actual figure.
Try it now with our salary calculator.
When to use one
Any time your pay situation changes. Got a raise? Run the numbers before you commit to a bigger flat. Considering a new job? Compare the offers on take-home, not gross. Starting pension contributions or changing your percentage? See how it actually affects what you receive.
Tax rules change every April too. The thresholds and rates the government sets can shift your take-home by hundreds of pounds a year, even if your salary stays the same.
Mistakes that cost people money
Wrong tax code. Your tax code tells your employer how much tax-free income you get. If it's wrong, you could be overpaying or underpaying tax all year without realising. The standard code for 2025/26 is 1257L. Check yours against the letter HMRC sent you.
Ignoring pension contributions. If you leave pension out of the calculation, you'll think you have more disposable income than you do. Budget on net pay after pension, not before.
Forgetting student loans. Plan 1, Plan 2, Plan 4, and postgraduate loans all have different thresholds and rates. Missing these from your calculation can throw off your monthly budget by over £100.
Tax terms worth knowing
PAYE stands for Pay As You Earn. Your employer deducts tax and NI from each payslip and sends it straight to HMRC. You never have to think about it unless something goes wrong.
Personal allowance is the amount you earn before tax kicks in: £12,570 for 2025/26. Once you earn over £100,000, you start losing it at a rate of £1 for every £2 above the threshold. By £125,140, it's gone entirely.
Tax code is a shorthand HMRC uses to tell your employer how much tax-free pay to give you. 1257L means you get £12,570 tax-free. If you see a K code, it means you owe extra. Worth checking.
For full details, see the income tax guidance on GOV.UK.
Get your actual number
Guessing what you take home is how budgets get blown and direct debits bounce. Spend thirty seconds with a salary calculator and plan your money around what you'll actually receive.