How to Calculate Annual Leave Entitlement (Full-Time & Part-Time)

Full-time entitlement

For a full-time employee who works the whole leave year, entitlement is simply your company's annual allowance — say 20 or 25 days. No calculation needed beyond setting the number.

Part-time: pro-rata by days worked

Part-timers get a proportional share of the full-time entitlement based on the days they work each week.

Example: if full-timers (5 days/week) get 28 days, someone working 3 days a week gets 3/5 × 28 = 16.8 days. A quick shortcut: days worked per week × (full-time entitlement ÷ 5).

Irregular hours: the 12.07% method

For staff with no fixed pattern, a common approach is to accrue holiday as a percentage of hours worked. The 12.07% figure comes from 5.6 weeks of statutory leave being 12.07% of the 46.4 working weeks in a year.

Formula: hours worked × 12.07% = holiday hours accrued. Work 30 hours and you accrue about 3.6 hours of paid leave.

Monthly accrual

To accrue annual leave monthly, divide the annual entitlement by 12. A 24-day allowance accrues 2 days per month; 160 hours accrues 13.33 hours per month.

Rules differ by country and contract, so confirm the method that applies to you. Whatever the method, the math is identical every period — which makes it ideal to automate.