Prorated PTO is a paid time off entitlement scaled to the portion of the year, or the portion of full-time hours, that an employee actually works. Someone who joins in April doesn’t get a full year’s allowance, and someone working three days a week doesn’t get the same allowance as someone working five.

Check out our Prorated PTO Calculator, a free Excel tool to figure out prorated time off in seconds.

When PTO gets prorated

• Mid-year joiners — entitlement covers only the remainder of the leave year
• Leavers — entitlement earned up to the final day, which then drives the payout calculation
• Part-time employees — scaled to hours or days worked against full-time
• Mid-year changes — a move to part-time, a change in contracted hours, or promotion into a higher entitlement tier

See also: The Ultimate Guide to Prorated PTO

How to calculate it

Mid-year joiner. Multiply the annual entitlement by the fraction of the leave year remaining.

Annual entitlement 20 days. Employee starts 1 April; leave year runs January to December. Nine months remain. 20 × (9 ÷ 12) = 15 days

For more precision, use days rather than months: 20 × (275 ÷ 365) = 15.07 days.

Part-time employee. Scale by the fraction of full-time hours.

Full-time is 40 hours a week with 20 days (160 hours) of PTO. Employee works 24 hours a week. 24 ÷ 40 = 0.6 160 × 0.6 = 96 hours

Mid-year change. This is the one that gets done wrong. Split the year at the change date, calculate each segment separately, and add them. Do not apply the new rate to the whole year.

Full-time January to June, then three days a week from July. Annual entitlement 20 days. First half: 20 × (6 ÷ 12) = 10 days Second half: 20 × 0.6 × (6 ÷ 12) = 6 days Total: 16 days

Applying the part-time rate retroactively would give 12 days — clawing back four days the employee already earned at the full-time rate. Where PTO is treated as an earned wage, that’s not just unfair, it’s a deduction from wages already accrued.

The part-time trap: days versus hours

A part-time employee’s “day” is not the same unit as a full-time employee’s day, and mixing them produces nonsense.

Someone working three days a week with a prorated 12 days of PTO has four weeks off — exactly the same as a full-timer with 20 days. Give that person 20 days instead and they have nearly seven weeks.

Prorating in hours rather than days removes the ambiguity entirely, and it’s the only approach that survives irregular schedules, compressed weeks, and mid-year changes. If your policy is written in days, state explicitly whose days they are.

The same trap applies to public holidays: prorating the holiday allowance is cleaner than granting whichever days happen to fall on a working day.

Rounding

Proration produces awkward numbers. 15.07 days, 96.4 hours.

Pick an increment — a half-day, a quarter-hour — apply it consistently, then decide direction and write it down. Rounding up, in the employee’s favour, is the safer default. Rounding down every time is a systematic shortfall across a workforce, and where PTO is treated as an earned wage, a policy that reliably rounds against employees is difficult to defend.

Apply it the same way to joiners and leavers. Rounding up on arrival and down on departure is the pattern auditors notice.

Where proration is set by law

Canada. Vacation pay is a percentage of wages actually earned — commonly 4%, rising to 6% with service in Ontario. Because the percentage attaches to earnings in the period, it prorates itself: a part-year employee earns the percentage on what they actually made, with no separate calculation. Vacation time for a partial period is prorated explicitly, as a fraction of the two- or three-week entitlement.

United Kingdom. For leave years beginning on or after 1 April 2024, irregular-hours and part-year workers accrue statutory holiday at 12.07% of hours actually worked in each pay period — a figure derived from 5.6 weeks’ leave across 46.4 working weeks. It applies to zero-hours and seasonal workers, not to someone on a fixed rotating shift pattern, who is prorated normally.

United States. No federal entitlement, so proration is a policy choice. But where state law treats accrued vacation as wages, you can prorate the forward entitlement, not the amount already accrued.

What you can’t prorate away

Proration applies to discretionary entitlement. It does not reduce statutory minimums below their floor, and several entitlements don’t prorate by year at all — FMLA leave is a fixed 12 weeks regardless of when in the year someone qualifies, and statutory sick leave usually accrues on its own schedule.

This entry is general information, not legal advice. Vacation-as-wages rules vary by US state and Canadian province.