How the pro rata salary calculator works
Pro rata means "in proportion". When a job advert says "£30,000 pro rata", that figure is the full-time equivalent (FTE) salary. If you work fewer hours than a full-time employee, you're paid the same share of that salary as the share of full-time hours you work. The hourly rate stays the same; you just work, and get paid for, fewer hours.
The calculator divides your hours by the full-time hours for the role, then multiplies the full-time salary by that fraction. You can compare by hours per week, which is the most accurate, or by days per week if every day is the same length.
Monthly pay is the yearly figure divided by 12, and weekly pay is the yearly figure divided by 52. These are gross figures, before income tax, National Insurance and pension. To see what you'd actually take home, put your pro rata salary into the take-home pay calculator.
Worked example: £30,000 pro rata for 22.5 hours
A full-time role pays £30,000 for 37.5 hours a week. You'll work 22.5 hours.
- Share of full time: 22.5 ÷ 37.5 = 0.6, so you're 0.6 FTE (60%)
- Pro rata salary: £30,000 × 0.6 = £18,000 a year
- Monthly: £18,000 ÷ 12 = £1,500
- Weekly: £18,000 ÷ 52 = £346.15
- Hourly rate (the same for full and part-time): £30,000 ÷ (37.5 × 52) = £15.38
If the full-time holiday allowance is 28 days, a 0.6 FTE worker gets 28 × 0.6 = 16.8 days.
Common pro rata salaries
For a 37.5-hour full-time week, here's what common part-time patterns pay on a £30,000 full-time salary:
| Hours a week | FTE | Pro rata salary | Monthly |
|---|---|---|---|
| 30 (4 days) | 0.8 | £24,000 | £2,000 |
| 22.5 (3 days) | 0.6 | £18,000 | £1,500 |
| 18.75 (2.5 days) | 0.5 | £15,000 | £1,250 |
| 15 (2 days) | 0.4 | £12,000 | £1,000 |
Hours or days: which should you use?
Use hours whenever you can. Days only work if your days are the same length as a full-time day. If a full-time week is 37.5 hours over five days (7.5 hours a day) and you work three 8-hour days, that's 24 hours, or 0.64 FTE, not the 0.6 you'd get by counting days. Over a year that's a £1,200 difference on a £30,000 salary.
Check whether the full-time hours include paid or unpaid breaks. Some employers use 37.5 hours, others 35, 39 or 40, and it changes the answer.
How pro rata holiday works
Part-time workers have the same right to paid holiday as full-time staff, scaled to the time they work. The legal minimum is 5.6 weeks a year: 28 days for someone working five days a week, or 16.8 days for someone working three. If your employer gives full-time staff more than the minimum, such as 25 days plus 8 bank holidays (33 days), your pro rata share is worked out the same way: 33 × 0.6 = 19.8 days.
Bank holidays catch people out. If you don't normally work on Mondays, you don't get a day off in lieu for Monday bank holidays, but your total allowance should still be pro rata. Many employers convert the allowance into hours to make this fair. Our holiday entitlement calculator works out the statutory minimum for any pattern.
Tips before you accept a part-time offer
- Ask for the full-time hours the salary is based on, not just the headline figure.
- Check you'll still clear the minimum wage: divide the pro rata salary by your yearly hours. From 1 April 2026 the National Living Wage is £12.71 an hour for workers aged 21 and over.
- Earnings under the Personal Allowance of £12,570 a year aren't taxed, so a lower pro rata salary can take you out of income tax altogether.
- Workplace pension auto-enrolment only kicks in once you earn over £10,000 a year with one employer, though you can usually ask to join below that.
- If you do extra hours, they're normally paid at your hourly rate unless your contract says otherwise. See the overtime calculator.
Frequently asked questions
What does £25,000 pro rata mean?
It means £25,000 is the salary for full-time hours, and you'll be paid a share of it based on the hours you work. On 18.75 hours of a 37.5-hour week (0.5 FTE) you'd earn £12,500 a year.
How do I calculate pro rata salary?
Divide your weekly hours by the full-time weekly hours, then multiply the full-time salary by the result. For example, 30 ÷ 37.5 = 0.8, and £30,000 × 0.8 = £24,000.
How much is 0.8 FTE?
0.8 FTE is 80% of full-time hours, usually four days a week. On a £35,000 full-time salary, 0.8 FTE pays £28,000 a year, or £2,333.33 a month before tax.
Do part-time workers get pro rata holiday?
Yes. Part-time workers are entitled to 5.6 weeks of paid holiday a year, the same as full-time workers, which works out at 16.8 days for a three-day week. Any extra contractual holiday is normally pro rata too.
Is the hourly rate the same for part-time work?
It should be. Part-time workers must not be treated less favourably than comparable full-time workers, so the pro rata salary keeps the same hourly rate. £30,000 for 37.5 hours a week is £15.38 an hour whether you work 15 hours or 37.5.
Last reviewed October 2026 using 2026/27 figures. This calculator gives an estimate for guidance only.