How to Calculate Pro Rata Holidays for Part-Time Workers

Start with the contract and actual pattern. A worker on the same two or three days each week has a fixed-days pattern. Someone with regular weekly hours but unequal shift lengths is usually clearer to manage in fixed hours. The statutory 12.07% accrual method is for workers who meet the legal definition of an irregular-hours worker or part-year worker, not simply anyone labelled casual or part-time.

GOV.UK's holiday entitlement guidance explains these categories and ACAS provides practical advice on calculating and recording leave. If the label and reality conflict, base the calculation on the real arrangement and seek advice before changing method.

For a worker who does the same number of days every week, multiply weekly working days by 5.6. The result is annual entitlement in that worker's days.

A three-day worker therefore receives 16.8 of their own working days, not three-fifths of a separate 28-day pot after bank holidays have been deducted. Do not round 16.8 down to 16. Record the fraction or round up under a consistently applied policy.

Use hours where shift lengths differ or a 'day' has no consistent value. Multiply normal weekly hours by 5.6. An employee contracted for 18 hours a week receives 100.8 hours of statutory leave a year.

Suppose the 18 hours are worked as eight hours on Monday, six on Wednesday and four on Friday. Taking Monday off uses eight holiday hours; taking Friday uses four. Deducting one day for each would distort entitlement. A worker whose hours are fixed but spread differently each week may also be easier to manage in hours, provided the conversion preserves a full 5.6 weeks of leave.

For leave years beginning on or after 1 April 2024, statutory leave for qualifying irregular-hours and part-year workers accrues each pay period at 12.07% of hours worked, subject to the statutory cap and rounding rules. GOV.UK explains the definitions and calculation.

If an irregular-hours worker completes 50 hours in a monthly pay period, the unrounded accrual is 50 × 12.07% = 6.035 hours. Apply the rounding required by the official method and keep the payroll working. Do not apply 12.07% to a regular three-day-a-week employee merely because they are part-time; that worker normally uses the 5.6-week fixed-pattern calculation.

A mid-year change should not erase leave already earned. Split the leave year into periods, calculate each fixed pattern for the relevant portion, then combine the results and subtract leave taken. For example, if someone moves from 18 to 24 fixed hours a week halfway through the leave year, calculate half a year at 100.8 annualised hours and half at 134.4 annualised hours.

For starters and leavers, pro-rate for the part of the leave year employed and check pay in lieu rules on termination. If a worker genuinely moves into or out of irregular-hours status, document the classification date rather than mixing 5.6-week and 12.07% methods across the same period without an audit trail.

There is no separate statutory right to paid bank holidays. An employer can include them within the 5.6-week minimum or offer them on top. The policy must not leave part-time workers worse off because of which weekdays they work.

For a three-day worker entitled to 16.8 days, a bank holiday closure on one of their normal working days can use part of that total if the contract says so. A worker who never works Mondays should not have Monday closures deducted. ACAS recommends a clear, proportionate approach; using one annual pot in days or hours often avoids giving a Monday worker materially different usable leave from a comparable Tuesday-to-Thursday worker.

Rolled-up holiday pay means adding holiday pay to each payslip while the worker takes the corresponding leave without a separate payment at that time. For leave years beginning on or after 1 April 2024, it is permitted only for qualifying irregular-hours and part-year workers. The holiday-pay amount must be calculated under the statutory method and shown separately on the payslip.

It is not permitted merely because a regular employee works part-time. A fixed-days or fixed-hours worker should normally receive holiday pay when leave is taken. Also distinguish entitlement from pay: paying a 12.07% uplift does not remove the worker's right and practical opportunity to take leave.

Use days for equal fixed working days, hours for fixed hours or unequal shifts, and 12.07% pay-period accrual only for workers who meet the irregular-hours or part-year definitions. Then pro-rate for any partial leave year, handle bank holidays consistently and preserve fractions rather than rounding down.

The holiday entitlement calculator can check days or hours, while the annual leave calculator helps track a broader leave balance. Keep the contract, rota and payroll record aligned, and compare unusual cases with current GOV.UK and ACAS guidance before finalising entitlement.