Pro-rata Salary Calculator
Work out your part-time pro-rata pay from a full-time salary and the hours you actually work.
Pro-rata salary
£20,000.00
50% of full-time · gross, before tax
- Per month
- £1,666.67
- Per week
- £384.62
What does pro-rata mean?
Pro-rata means "in proportion". A pro-rata salary is a full-time salary scaled down to the hours you actually work. If a role is advertised at £30,000 full-time for 37.5 hours a week and you work 22.5 hours, your pro-rata salary is the same proportion of the full-time figure.
This calculator divides your hours by the full-time hours and multiplies the full-time salary by that fraction, then shows the annual, monthly and weekly equivalent.
Pro-rata and your entitlements
Part-time workers are entitled to the same benefits as full-time colleagues on a pro-rata basis, including holiday. For example, someone working three days a week gets three-fifths of the full-time holiday allowance.
Pro-rata figures here are gross (before tax). To see take-home pay on a part-time salary, run the result through the salary calculator.
Worked example
A £40,000 full-time salary based on 37.5 hours a week, worked at 18.75 hours (half time), gives a pro-rata salary of £20,000 a year.
That is about £1,667 a month before tax.
Frequently asked questions
Is this before or after tax?
It is a gross pro-rata figure. Use the salary calculator to see take-home pay after Income Tax and National Insurance.
What full-time hours should I use?
Use the employer's full-time hours for the role, commonly 35 to 40 hours a week. The advert or contract will state this.
Does pro-rata apply to holiday too?
Yes. Holiday, and most other benefits, are given to part-time staff in proportion to their hours.
Can it handle more than full-time hours?
Yes. If you enter hours above full-time it scales the salary up proportionally, though overtime is often paid differently.
Figures last reviewed on 13 August 2025.
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