The short answer
Pro-rata salary = full-time salary × your hours ÷ full-time hours. A £30,000 job at 37.5 hours a week, worked for 22.5 hours, pays £30,000 × 22.5 ÷ 37.5 = £18,000 a year. Your holiday is pro-rated the same way: 5.6 weeks of whatever your working week is.
Part-time job adverts in the UK often show two numbers: “£30,000 pro rata” and a line further down saying the role is three days a week. The £30,000 is what the job would pay if you worked full time. What lands in your account is a share of it, in proportion to your hours — that's all “pro rata” means.
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How to work it out
- 1Find the full-time hours for the role. It's usually in the advert or contract — 35, 37.5 and 40 are the common ones.
- 2Divide your weekly hours by the full-time hours. 22.5 ÷ 37.5 = 0.6, so you work 60% of full time.
- 3Multiply the full-time salary by that figure. £30,000 × 0.6 = £18,000.
Working in days instead? Use days: three days out of five is also 0.6. Just don't mix them — if your days are longer or shorter than a full-time day, go by hours.
Paid by the hour instead? Our hourly to salary table shows what common hourly rates add up to over a year.
Pro-rata salary examples
| Your hours a week | Share of full time | Pro-rata salary | Per month |
|---|---|---|---|
| 30 (4 days) | 80% | £24,000 | £2,000 |
| 22.5 (3 days) | 60% | £18,000 | £1,500 |
| 18.75 (half time) | 50% | £15,000 | £1,250 |
| 15 (2 days) | 40% | £12,000 | £1,000 |
Pro-rata holiday entitlement
In the UK almost everyone is entitled to 5.6 weeks of paid holiday a year. Part-time workers get the same 5.6 weeks — but a week for them is shorter. So the formula is simply 5.6 × the days (or hours) you work in a week:
| Days worked a week | Holiday a year |
|---|---|
| 1 | 5.6 days |
| 2 | 11.2 days |
| 3 | 16.8 days |
| 4 | 22.4 days |
| 5 | 28 days (the maximum) |
What about bank holidays?
The 5.6 weeks can include bank holidays — employers don't have to give them on top. Part-time staff who don't normally work on Mondays still get the pro-rata entitlement; it shouldn't be reduced just because many bank holidays fall on their day off.Employers who give more than the legal minimum — say 25 days plus bank holidays — must pro-rate the extra for part-timers too.
Things to check in a part-time offer
- Which full-time hours they used. £30,000 pro rata on a 35-hour week pays more per hour than the same figure on a 40-hour week.
- Whether overtime is paid at the overtime rate. Part-timers often only get enhanced rates once they go past full-time hours, not their own contracted hours.
- Pension and benefits. Workplace pension contributions are a percentage of what you actually earn, so they're pro-rated automatically.
- Tax. A lower salary may fall under the personal allowance or a lower band, so your take-home pay drops by less than your hours do. Check the GOV.UK estimate for your figure.
Frequently asked questions
What does pro rata mean in a salary?
It means the advertised salary is the full-time amount. You'll be paid a share of it in proportion to the hours you work.
How do I calculate pro rata salary for 3 days a week?
Multiply the full-time salary by 3 and divide by 5 (if full time is five days of the same length). £30,000 becomes £18,000.
How many days holiday do I get working 3 days a week?
16.8 days a year under UK law: 5.6 weeks × 3 days. Many employers round up to 17.
Is my hourly rate lower on a pro rata salary?
No. Pro rata pay keeps the same hourly rate as the full-time job — you're just paid for fewer hours.
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