Pro rata salary calculator — see what part-time actually pays
Enter the full-time salary and your hours (or FTE fraction) — we'll work out your pro-rata pay and run the full tax and NI breakdown on it.
A pro-rata salary is the full-time salary scaled by the share of full-time hours you work. Working 22.5 of 37.5 hours (60%) on a £45,000 full-time salary gives £27,000 — which leaves £22,959.60 a year (£1,913/month) after tax and NI in 2025/26. Your personal allowance doesn't shrink with your hours, so part-time pay keeps a higher share of every pound.
- Personal allowance
- £12,570
- Applies in
- England, Scotland & Wales supported
- Calculation
- Hours ÷ full-time hours × salary
Parsed as: 1257L (£12,570 allowance, England & NI)
How pro rata works
“Pro rata” simply means “in proportion”. Your salary is the full-time rate scaled by the fraction of full-time hours you work — 22.5 hours of a 37.5-hour week is 0.6, so a £45,000 role pays £27,000. The same fraction applies to holiday entitlement and to percentage-based benefits.
What does not scale is the tax system. Your personal allowance stays at £12,570 however few hours you work, and the tax bands sit at the same thresholds. That’s why part-time take-home is proportionally better than full-time: a bigger share of a smaller salary fits inside the tax-free allowance and the basic rate band.
When employers use pro rata
- Part-time roles advertised with a full-time-equivalent (FTE) salary.
- Term-time-only contracts in schools, annualised over 12 months.
- Contract or fixed-term roles covering part of a year.
- Job shares, where two people split one full-time salary by hours.
- Starting or leaving a job part-way through a pay period.