Pro Rata Salary Calculator
A job advertised at a full-time salary pays proportionally less if you work fewer hours. Enter the full-time salary and hours, then your actual hours, to see your pro-rata gross pay — and what it means after tax.
How it works
Pro-rata pay = full-time salary × (your hours ÷ full-time hours). A £30,000 FTE role at 37.5 hours worked 20 hours a week pays £16,000 gross. Holiday entitlement scales the same way.
The tax outcome is disproportionately favourable for part-timers: the £12,570 Personal Allowance does not shrink, so a larger share of a part-time salary is tax-free. £16,000 part-time keeps about 94% of gross, while the full £30,000 keeps about 85%.
This calculator assumes hours-based pro-rating, the standard approach. Some employers pro-rate by days worked — the arithmetic is the same with days in place of hours.
FAQ
How do I work out pro rata salary?
Divide your weekly hours by the full-time hours and multiply by the advertised salary. Example: 25 hours on a 37.5-hour, £33,000 FTE role = 25 ÷ 37.5 × £33,000 = £22,000 gross. Holiday days, pension contributions and bonuses normally scale by the same fraction.
What does "£30,000 pro rata" mean in a job advert?
It means £30,000 is the full-time equivalent (FTE) — you receive the proportion matching your hours. At 22.5 hours against a 37.5-hour full-time week you would actually be paid £18,000 a year. Always check the advert's full-time hours, as 35, 37.5 and 40-hour baselines change the result.
Is tax also pro-rated for part-time workers?
No — tax bands and the Personal Allowance stay the same regardless of hours, which works in your favour: a bigger fraction of a smaller salary sits inside the tax-free £12,570. Working 50% of hours therefore leaves you with more than 50% of the full-time take-home pay.