How to calculate pro-rata holiday entitlement (UK)
Last updated: 25 July 2026
When someone works part-time, or joins part-way through your leave year, they don’t get the full annual allowance — they get a pro-rata (proportional) amount. Here’s how to work it out.
Not legal advice. This guide explains the common calculations. Always check current GOV.UK holiday entitlement guidance for your specific situation.
What does “pro rata” mean for holiday?
Pro rata simply means “in proportion”. If a full-time employee gets 28 days, a part-time employee gets a share of that in proportion to the days or hours they work compared with full time.
Pro rata for part-time staff (by days per week)
The simplest method uses the statutory 5.6 weeks:
Days worked per week × 5.6 = annual entitlement (in days)
Worked examples
- 3 days a week: 3 × 5.6 = 16.8 days
- 4 days a week: 4 × 5.6 = 22.4 days
- 2.5 days a week: 2.5 × 5.6 = 14 days
You can round up (rounding down below the statutory minimum isn’t allowed), or track fractional days directly.
Pro rata for a mid-year starter
If someone joins part-way through the leave year, pro-rate their annual allowance by the portion of the year remaining.
Formula:
(Months remaining ÷ 12) × full annual entitlement
Worked example
A full-time employee (28 days) starts with 9 months left in the leave year:
(9 ÷ 12) × 28 = 21 days
For finer accuracy you can calculate by days remaining instead of whole months:
(Days remaining in leave year ÷ 365) × annual entitlement
Pro rata by hours (for irregular shifts)
If your team works variable hours, it’s often clearer to hold entitlement in hours rather than days:
Contracted hours per week ÷ full-time hours per week × full-time holiday hours
For example, if full time is 40 hours with 224 holiday hours (28 days × 8), someone on 24 hours a week gets:
24 ÷ 40 × 224 = 134.4 holiday hours
Let LeaveTrac do the maths
LeaveTrac Pro includes a built-in pro-rata holiday calculator, so you don’t have to reach for a spreadsheet. Set an employee’s working pattern, and LeaveTrac works out their entitlement and keeps the running balance as leave is booked.
New to how UK entitlement works overall? Start with UK statutory holiday entitlement explained.
Summary
- Part-time: days per week × 5.6
- Mid-year starter: (months remaining ÷ 12) × annual entitlement
- By hours: contracted ÷ full-time × full-time holiday hours
- Never round a result below the statutory minimum