How pro-rata pay works
“Pro rata” means in proportion. A pro-rata salary is the full-time salary scaled to the hours you actually work:
Pro-rata salary = full-time salary × your hours ÷ full-time hours
You can work it out three ways in the calculator:
- Hours a week: for example 22.5 of 37.5 hours.
- Days a week: for example 3 of 5 days.
- Percentage of full time (FTE): for example 0.6 FTE = 60%, the format used in many NHS, education and public-sector adverts.
Part-time on a £30,000 salary
| Share of full time | Pro-rata salary | Take-home a year | Take-home a month | Share of full-time take-home |
|---|---|---|---|---|
| 40% | £12,000 | £12,000 | £1,000 | 48% |
| 60% | £18,000 | £16,480 | £1,373 | 66% |
| 80% | £24,000 | £20,800 | £1,733 | 83% |
Full-time take-home on £30,000 is £25,120 a year. Because your tax-free Personal Allowance and the 20% band aren’t pro-rated, a part-time salary is taxed less, so you keep more than your pro-rata share of the full-time take-home. The calculator also shows your take-home per hour actually worked, which is often higher part-time.
Pro-rata holiday entitlement
Part-time workers have the same right to paid holiday as full-time colleagues, in proportion. The legal minimum is 5.6 weeks a year:
- 5 days a week: 28 days (the statutory maximum)
- 4 days a week: 22.4 days
- 3 days a week: 16.8 days
- 2 days a week: 11.2 days
If your employer gives full-time staff more, say 25 days plus 8 bank holidays (33), you should get the same proportion. The calculator shows your entitlement in days and in hours (useful if your shifts vary in length), and warns you if it works out below the statutory minimum for the days you work.
Bank holidays are a common source of disputes. Part-timers don’t get “extra” days because a bank holiday falls on a day they don’t work, but they also shouldn’t lose out. Most employers give everyone a pro-rata allowance that includes bank holidays.
Starting or leaving part-way through the year
If you join or leave during the year, switch on Only employed for part of the year and enter your dates. Pay for the period is:
annual (pro-rata) salary × days employed ÷ 365
Holiday is pro-rated the same way. For take-home, we assume you had no other taxable income in the same tax year, so your full Personal Allowance applies. In reality PAYE spreads it across the year, so a refund may be due if you stop working before April.
Things that aren’t pro-rated
- Your Personal Allowance and tax bands, which is why part-time take-home is proportionally higher.
- Student loan thresholds. A lower salary may drop you below the repayment threshold altogether.
- Pension auto-enrolment. You’re auto-enrolled only if you earn over £10,000 a year, and contributions are based on earnings above £6,240.
- Benefits in kind and allowances depend on your contract. Some are pro-rated, some aren’t.
Next steps
Need a particular amount to live on? The required salary calculator works backwards from take-home pay. Then rebuild your monthly spending in the budget planner.
Frequently asked questions
How do I calculate a pro-rata salary?
Divide your hours by the full-time hours and multiply by the full-time salary. 22.5 hours on a 37.5-hour, £30,000 job is 60%, so £18,000 a year.
How much holiday do part-time workers get?
The same 5.6 weeks as full-time staff, pro-rated. Someone working 3 days a week is entitled to at least 16.8 days (5.6 × 3), including bank holidays. If your employer gives full-timers more, part-timers should get the same proportion.
Do I keep more than the pro-rata share of take-home?
Usually yes. Your Personal Allowance and lower tax bands aren't reduced, so a smaller salary is taxed less. On £30,000, working 60% of the hours keeps about 66% of the full-time take-home.
How is pay worked out if I start part-way through the year?
Multiply the annual salary by the days you're employed and divide by 365. Starting on 1 October and working to 5 April is 187 days, so about 51% of a year's pay.
Is FTE the same as pro-rata?
FTE (full-time equivalent) is the fraction of full-time you work, such as 0.6. The pro-rata salary is the full-time salary multiplied by your FTE.
Can my employer pay part-timers a lower hourly rate?
No. Under the Part-time Workers Regulations, part-timers must not be treated less favourably than comparable full-timers, including on hourly pay, unless the employer can objectively justify it.
Does working part-time affect my pension?
Contributions are a percentage of your (lower) pay, so less goes in. See the effect over time in the pension calculator.
Sources
Results are estimates for education and planning, not financial advice. They depend on the figures you enter and the assumptions shown above.