UK HR Term
Pro-rata
Pro-rata is the principle of allocating a benefit, entitlement, or payment in proportion to the time worked or fraction of a full unit. Most commonly applied in UK HR to part-time workers' holiday and pay.
In plain English
Pro-rata (Latin: "in proportion") is the principle of allocating a benefit, entitlement, or payment in proportion to the time worked or the fraction of a full unit. Most often used in UK HR for part-time staff and mid-year starters.
Common uses
- Holiday entitlement — a 3-day-a-week worker gets 3/5 of the full-time allowance.
- Salary — annual salary divided by months or weeks for mid-year starters and leavers.
- Bonus — a bonus paid for partial-year service is usually pro-rated against full-year service.
- Bank holidays — pro-rated separately from general holiday so part-timers aren't disadvantaged by the days bank holidays fall on.
The arithmetic
Two ways the calculation is usually expressed:
- By fraction of full-time — 0.6 FTE × 25 days = 15 days
- By time worked — (months worked ÷ 12) × annual entitlement
Both arrive at the same answer for simple cases. The fraction approach is cleaner for ongoing part-timers; the time-worked approach is cleaner for starters and leavers.
Common mistake
Forgetting to pro-rate bank holidays separately for part-timers who don't work Mondays. Bank holidays disproportionately fall on Mondays, so a 4-day-a-week non-Monday worker would be cheated out of nearly all bank holiday entitlement under a flat pro-rata rule.