Pro Rata Salary Calculator — 2026/27
Pro rata means “in proportion”. If a full-time job pays £40,000 for five days a week and you work three days, your pro rata salary is three-fifths of £40,000 — £24,000. Enter the full-time salary and your working days, and this calculator works out your pro rata gross pay and what you take home after tax.
| Gross salary | — |
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| Personal Allowance | — |
| Income tax | — |
| National Insurance | — |
| Pension | — |
| Student loan | — |
| Overall deduction rate | — |
Income tax by band
| Band | Taxed amount | Tax |
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Pension is modelled as a net pay arrangement (it reduces taxable pay, not National Insurance). Student loan thresholds 2026/27: Plan 1 £26,900 · Plan 2 £29,385 · Plan 4 £33,795 · Plan 5 £25,000 · Postgraduate £21,000.
How pro rata pay is calculated
The formula is simple: full-time salary × (your days ÷ full-time days). The same fraction applies to holiday entitlement — a three-day worker gets three-fifths of the full-time holiday allowance (with a legal minimum of 5.6 weeks of your own working pattern). Tax and National Insurance are then worked out on your actual pro rata salary, which is why part-time pay often keeps a bigger share: more of it sits inside the tax-free Personal Allowance.
Frequently asked questions
What is the pro rata salary for 3 days a week on £40,000?
Three days is 3/5 of full time, so the pro rata salary is £24,000. In 2026/27 that leaves £20,727.60 take-home in England, Wales or Northern Ireland.
Is pro rata pay taxed differently?
No — the same tax bands and Personal Allowance apply. Because the salary is lower, a smaller share is taxed, so the percentage you keep is usually higher than the full-time equivalent.
How does pro rata holiday work?
Your holiday scales by the same fraction. Full-time 25 days becomes 15 days for a three-day week, and the statutory minimum is 5.6 weeks of your normal working week.