How we calculate
Pay figures matter, so you should be able to see where they come from and where they stop being reliable.
This page covers our pro rata salary, salary sacrifice and overtime calculators, which all share the same engine.
The method
Income Tax is worked out on the whole tax year, as cumulative PAYE does, using the standard 1257L allowance. The personal allowance falls by £1 for every £2 of adjusted net income above £100,000.
National Insurance is worked out month by month with category A rates, as a monthly payroll does. Annual figures can differ from a yearly calculation by a few pounds as a result.
Student loans are also worked out on each month's pay, at 9% above the plan threshold and 6% for Postgraduate Loans. They use pay after salary sacrifice, but before net pay pension contributions.
Pensions follow the method you choose. Salary sacrifice reduces pay before all deductions. Net pay reduces pay for Income Tax only. Relief at source comes out of take-home, with 20% added by the provider, and we show any further relief as an amount to reclaim.
What we assume
- You have one job, and no other income or benefits.
- You're paid monthly, in equal amounts unless you choose otherwise.
- Your tax code is 1257L, on a cumulative basis.
- You're under State Pension age and pay category A National Insurance.
- A year has 52 paid weeks when converting salaries to hourly rates.
- A working day is a fifth of the full-time week, unless you set your own weekly pattern.
- Term-time holiday is 5.6 weeks for every 46.4 weeks worked, unless you enter your contract's figure.
What we don't cover
- Taxable benefits, such as a company car, and tax code adjustments.
- Weekly or four-weekly pay dates, which change NI slightly.
- Directors' NI, self-employment and umbrella companies.
- The tapered annual allowance and carry forward of unused allowance.
- Salary sacrifice for anything other than pensions.
- Holding two student loan plans of different types at once. Choose your main plan.
Treat every result as an estimate. Before a decision that matters, check it against your payslip, your contract or a regulated adviser.
How we test it
The calculators run on one shared engine, which has 79 automated checks. They cover hand-worked figures from the GOV.UK rates, published worked examples, the band limits, and rules that must always hold, such as every pound of gross pay being accounted for.
A worked example you can check
Here's a £36,000 salary in England, with no pension or student loan, worked through by hand. Enter the same figures in any calculator and you'll get the same result.
| Salary | £36,000 |
|---|---|
| Income Tax: 20% of £36,000 minus £12,570 | £4,686 |
| NI: 8% of £3,000 minus £1,048, for 12 months | £1,874 |
| Take-home for the year | £29,440 |
| Take-home a month | £2,453 |
How we keep it accurate
- Each figure is read from an official source, and every source is listed on this page.
- We update the rates for each new tax year and when the rules change.
- Any change to our figures or methods is recorded at the bottom of this page.
- Every change must pass our automated checks before it goes live.
We aren't regulated advisers, and no regulated tax or financial adviser has reviewed this site.
2026/27 rates we use
Income Tax: England, Wales and Northern Ireland
| Personal allowance | £12,570 |
|---|---|
| Basic rate 20% | Taxable income to £37,700 |
| Higher rate 40% | £37,701 to £125,140 |
| Additional rate 45% | Above £125,140 |
Income Tax: Scotland
| Starter 19% | Up to £3,967 above the allowance |
|---|---|
| Basic 20% | £3,968 to £16,956 |
| Intermediate 21% | £16,957 to £31,092 |
| Higher 42% | £31,093 to £62,430 |
| Advanced 45% | £62,431 to £125,140 |
| Top 48% | Above £125,140 |
National Insurance, category A
| Lower earnings limit | £559 a month |
|---|---|
| Primary threshold | £1,048 a month |
| Upper earnings limit | £4,189 a month |
| Employee rate | 8% to the upper limit, then 2% |
| Employer rate | 15% above £417 a month |
Student loans
| Plan 1 | £26,900 a year at 9% |
|---|---|
| Plan 2 | £29,385 a year at 9% |
| Plan 4 | £33,795 a year at 9% |
| Plan 5 | £25,000 a year at 9% |
| Postgraduate | £21,000 a year at 6% |
Other figures
| National Living Wage (21+) | £12.71 |
|---|---|
| Age 18 to 20 | £10.85 |
| Under 18 and apprentices | £8.00 |
| Statutory holiday | 5.6 weeks, capped at 28 days |
| Pension annual allowance | £60,000 |
| Child Benefit charge | £60,000 to £80,000 adjusted net income |
| Pension auto-enrolment trigger | £10,000 |
Official sources
- GOV.UK: Rates and thresholds for employers 2026 to 2027
- GOV.UK: Income Tax rates and allowances
- GOV.UK: National Minimum Wage and National Living Wage rates
- GOV.UK: Holiday entitlement
- GOV.UK: Holiday pay
- Acas: Pay for working extra hours
- GOV.UK: Overtime: your rights
- GOV.UK: Maximum weekly working hours
- GOV.UK: Salary sacrifice for employers
- GOV.UK: Salary sacrifice reform for pension contributions from 6 April 2029
- GOV.UK: Tax on your private pension contributions
- GOV.UK: Pension annual allowance
- GOV.UK: High Income Child Benefit Charge
- GOV.UK: Adjusted net income
- GOV.UK: Review of the automatic enrolment earnings trigger for 2026/27
- GOV.UK: Part-time worker rights
- Acas: Part-time workers
Changes
5 November 2026: Added more guidance to the calculator pages. No rates or methods changed.
4 November 2026: First version, using 2026/27 rates, checked against the official sources above.