How do I calculate a pro-rata salary?

Divide the contracted weekly hours by the full-time weekly hours to get the FTE, then multiply the full-time salary by it. A 48,000 salary for 37.5 hours, worked at 22.5 hours, is 0.6 × 48,000 = 28,800.

Is a part-time hourly rate the same as full-time?

It should be. Pro-rating the salary by hours keeps the rate per hour identical, and many countries require part-time workers to be treated no less favourably than comparable full-time staff.

How is holiday worked out for part-time staff?

Multiply the full-time entitlement by the FTE, and by the share of the year employed for a part year. Rounding is normally up to the next half or whole day, since rounding down can fall below a statutory minimum.

Should a part year be pro-rated by working days or calendar days?

Either is used, and they give slightly different pay for the same dates. Contracts or payroll policy usually say which; what matters most is applying the same method to everyone.

Does anything I type get sent anywhere?

No. The whole calculation runs in your browser. Nothing is sent to us or logged, and there is no account to create. Your browser keeps the figures with this tab’s history so that Back and Reload bring them back, and Reset clears them.

Pro-Rata Salary & Part-Time FTE Calculator

Turn a full-time salary into part-time pay, FTE and leave, for a full or part year.

Replaces: Payroll department spreadsheets

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How to use it

Enter the full-time salary and week, the hours in the part-time contract and the full-time leave entitlement. For someone joining or leaving part-way through the year, enter the working days and calendar days they are employed and choose which count decides the pay.

Where the number comes from

FTE is contracted hours ÷ full-time hours. The pro-rata salary is the full-time salary × FTE, and monthly pay is a twelfth of it.
Pay for the period employed is the pro-rata salary × working days employed ÷ working days in the year, or × calendar days employed ÷ 365.
Leave is the full-time entitlement × FTE × the same share of the year, rounded up to the next half day.
The hourly rate is the full-time salary ÷ (full-time hours × 52). The part-time salary ÷ (contracted hours × 52) gives the same figure.

What goes wrong

The part most calculators leave out.

Leave in days misleads when part-timers work full days on fewer days a week. Someone on three full days needs three days off to take a week; leave measured in hours avoids the mismatch, which is why the notes give an hours figure.
Public holidays are where pro-rata leave usually goes wrong. If the full-time figure includes them, a part-timer whose working days miss most bank holidays can end up with more or fewer days off than the proportion intended.
The two part-year methods give different answers for the same dates. Using working days for one employee and calendar days for another treats them differently; pick one method and use it consistently.
Fifty-two weeks is a convention: a year is slightly over 52 weeks, so an hourly rate worked out from an annual salary is a little higher than one from 52.14 weeks, and payroll systems differ.
Hours are taken as fixed. Annualised or term-time contracts pro-rate over a different number of weeks, and the simple hours ratio does not apply.

A 22.5-hour contract starting halfway through the year

The role pays 48,000 for a 37.5-hour week. A 22.5-hour contract is 0.6 FTE, so the pro-rata salary is 28,800, or 2,400 a month. The hourly rate is 24.62 either way. The employee starts on 1 July: 132 of 261 working days, so pay for the period is 14,565.52. Counted in calendar days — 184 of 365 — it would be 14,518.36, 0.32% less. Leave is 25 days × 0.6 × the share of the year, 7.59 days, rounded up to 8.

Questions

How do I calculate a pro-rata salary?: Divide the contracted weekly hours by the full-time weekly hours to get the FTE, then multiply the full-time salary by it. A 48,000 salary for 37.5 hours, worked at 22.5 hours, is 0.6 × 48,000 = 28,800.
Is a part-time hourly rate the same as full-time?: It should be. Pro-rating the salary by hours keeps the rate per hour identical, and many countries require part-time workers to be treated no less favourably than comparable full-time staff.
How is holiday worked out for part-time staff?: Multiply the full-time entitlement by the FTE, and by the share of the year employed for a part year. Rounding is normally up to the next half or whole day, since rounding down can fall below a statutory minimum.
Should a part year be pro-rated by working days or calendar days?: Either is used, and they give slightly different pay for the same dates. Contracts or payroll policy usually say which; what matters most is applying the same method to everyone.
Does anything I type get sent anywhere?: No. The whole calculation runs in your browser. Nothing is sent to us or logged, and there is no account to create. Your browser keeps the figures with this tab’s history so that Back and Reload bring them back, and Reset clears them.

Last updated 18 October 2026.

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