Pro Rata Calculator UK

How to Calculate Pro Rata Salary in the UK

A pro rata salary is a full-time salary scaled proportionally to reflect the hours or days actually worked. If a role is advertised at £35,000 FTE (full-time equivalent) and you work 3 days out of a standard 5-day week, your pro rata salary is £35,000 × (3 ÷ 5) = £21,000.

The pro rata formula

Pro Rata Salary = FTE Salary × (Your hours or days ÷ Full-time hours or days)

For part-year workers (such as term-time staff), multiply by a second fraction:

Pro Rata Salary = FTE Salary × (Your hours ÷ FTE hours) × (Your weeks ÷ 52)

Hours vs days — which should you use?

Use hours when your contract specifies a number of hours per week (e.g. 22.5 hours out of 37.5). Use days when you work whole days and your contract specifies days per week (e.g. 3 days out of 5). Both methods give the same result if your daily hours are consistent.

Part-year and term-time contracts

Workers on term-time or seasonal contracts work fewer than 52 weeks per year. Their pro rata salary reflects both the reduced weekly hours and the shorter working year. For example, a teaching assistant working 37.5 hours a week for 39 weeks on a £28,000 FTE salary would receive:

£28,000 × (39 ÷ 52) = £21,000 pro rata

Pro rata holiday entitlement

Part-time workers are entitled to the same proportion of statutory annual leave as full-time colleagues. The statutory minimum is 5.6 weeks per year (28 days for a 5-day week). A part-time worker doing 3 days a week is entitled to 5.6 × 3 = 16.8 days. Use our Holiday Entitlement Calculator to calculate your exact figure.

Pro Rata Salary Quick Reference

Common FTE to part-time conversions at typical UK salaries:

Use the calculator above for any salary and working pattern — including part-year and term-time contracts.

Bank Holidays for Part-Time Workers

Bank holidays are one of the most misunderstood areas of part-time pay. The rules:

• Part-timers are entitled to a pro-rata share of bank holidays — not to the same number of days as full-timers. For a 3-day week: (3 ÷ 5) × 8 = 4.8 bank holiday days per year.
• You cannot simply give them the bank holidays that fall on their working days. If a part-timer works Tuesday–Thursday and all 8 bank holidays fall on Mondays, they cannot receive zero bank holiday days — they are entitled to 4.8 days and must be given equivalent time off on their working days, or paid in lieu.
• The cleanest solution: include bank holiday entitlement within the total holiday allowance (for example, 22.4 days total for a 4-day week, which includes the pro-rata bank holiday allocation of 6.4 days).

Pro Rata Sick Pay and SSP

Statutory Sick Pay (SSP) works slightly differently for part-time employees. SSP is £123.25/week regardless of working pattern — it is not reduced pro-rata for part-timers. However:

• SSP is only paid for qualifying days — the days the employee normally works
• A 3-day week worker off sick for a week receives SSP for 3 qualifying days, not 5
• The daily SSP rate for a 3-day week worker is higher than for a 5-day worker (same weekly rate, fewer days)
• If a part-timer earns less than £123.25/week, they receive 80% of their average weekly earnings instead of the flat SSP rate

Use the SSP calculator and select the appropriate qualifying days per week for accurate figures.

Is My Pro Rata Salary Correct? A Quick Check

If you think your part-time salary may be wrong, use this check:

1. Find the FTE salary for your role — it should be in your contract or job advertisement
2. Divide your actual hours (or days) by the full-time hours (or days): e.g. 22.5 ÷ 37.5 = 0.6
3. Multiply the FTE salary by this fraction: e.g. £35,000 × 0.6 = £21,000
4. Compare this to your actual salary. If it is materially different, raise it with HR or your employer

The Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000 give part-timers the right to the same hourly pay as comparable full-timers. If you are being paid less per hour for the same role, that is unlawful.

Common Employer Mistakes with Pro Rata Pay

• Using the wrong FTE hours — always use the contractual full-time hours for the role (e.g. 37.5 hours), not a round number like 40.
• Forgetting to pro-rate bank holidays — giving part-timers only the bank holidays that fall on their working days, rather than their pro-rata entitlement.
• Not adjusting when hours change — if a part-timer increases their hours, recalculate both salary and holiday entitlement from the date of change.
• Breaching National Minimum Wage — always verify the hourly rate is above the NMW floor for the employee's age. For 2026/27: £12.71/hour (21+), £10.85/hour (18–20).
• Treating term-time workers as self-employed — term-time contracts are employment contracts; SSP, SMP, and holiday entitlement all apply.

Pro Rata and Your Wider Employment Costs

A part-time hire still carries employer NI, pension, and statutory entitlement costs — just proportionally smaller. Use our calculators to model the full picture:

• Employee Cost Calculator — total employer cost at any pro-rata salary including NI and pension
• Holiday Entitlement Calculator — exact leave entitlement for any part-time working pattern
• SSP Calculator — sick pay for part-time employees, by qualifying days

Further Reading

• Employer Payroll Costs 2026/27 — The Complete Guide — every employment cost in one place: NI, pension, SSP, SMP, holiday and NMW
• Holiday Entitlement for Part-Time Workers — pro-rata leave calculations, bank holidays, and common mistakes explained
• UK Statutory Holiday Entitlement 2026/27 — full holiday entitlement rules, carry-over, and holiday pay calculation