Use the calculator
How this calculator works
Many part-time jobs are advertised with a "full-time equivalent" (FTE) salary followed by "pro rata". That means you will be paid a share of the full-time salary in line with the hours you work. The calculator works it out like this:
- Hours fraction = your hours ÷ full-time hours.
- Weeks fraction = weeks you work ÷ 52. Leave this at 52 if you work all year.
- Pro-rata salary = FTE salary × hours fraction × weeks fraction.
It shows your yearly and monthly gross pay, your fraction of a full-time post, and the hourly rate implied by the full-time salary. The results are before tax and other deductions. For take-home pay, put the pro-rata salary into the take-home pay calculator.
The weeks setting is a simple model for term-time contracts. Real term-time pay is often worked out with a formula that adds paid holiday to the weeks worked, so the figure your employer uses may be higher. Check your contract or ask your employer how they work it out.
Worked examples
These figures come from running this calculator and were checked by hand.
Example 1: three days a week
A £30,000 FTE job for 22.5 hours instead of 37.5 is 60% of full time. Pro-rata salary is £18,000 a year, or £1,500 a month. The FTE hourly rate is £15.38.
Example 2: term-time only
A £26,000 FTE post for 37 hours a week, paid for 39 weeks of the year, gives a fraction of 75%. The simple pro-rata salary is £19,500 a year, or £1,625 a month. Your employer’s figure may be higher if paid holiday is added to the 39 weeks.
Example 3: four days a week
A £45,000 FTE job on a 35-hour week, worked as 28 hours, is 80% of full time: £36,000 a year, or £3,000 a month.
Quick reference: fractions of a 37.5-hour week
| Hours per week | Fraction | £30,000 FTE becomes |
|---|---|---|
| 30 | 80% | £24,000 |
| 22.5 | 60% | £18,000 |
| 18.75 | 50% | £15,000 |
| 15 | 40% | £12,000 |
| 7.5 | 20% | £6,000 |
Assumptions and what this calculator does not cover
- Gross pay only: it does not deduct tax, National Insurance, pension or student loans.
- Term-time formulas: employers, especially schools and councils, often use their own method to include holiday pay. The simple weeks fraction here may not match it.
- Allowances and overtime: pay supplements, overtime and shift allowances are not included.
- Minimum wage: it does not check that the hourly rate is at least the legal minimum.
Part-time workers’ rights
Part-time workers should not be treated less favourably than comparable full-time workers. In practice, that usually means the same hourly rate, the same access to pension schemes and training, and holiday and other benefits worked out pro rata. Statutory holiday is 5.6 weeks a year. For someone who works three days a week, that is 16.8 days.
Pro rata and tax
Because tax and National Insurance thresholds are fixed amounts, take-home pay does not fall in proportion when you reduce your hours. The first £12,570 is covered by the Personal Allowance, and National Insurance only starts above £12,570 a year, so a lower salary may keep more of each pound. If you are deciding whether to cut your hours, compare take-home pay for both salaries rather than gross pay. Remember that pension contributions linked to salary will also fall.
Thinking of changing your hours? Employees with the right to request flexible working can ask their employer, who has to consider the request properly. A lower salary can also affect benefits such as Universal Credit and the amount you can borrow on a mortgage.
Checking your contract
Your contract or offer letter should state your hours, your pay and how holiday is worked out. If the figures do not match what this calculator shows, ask your employer which full-time hours and which formula they used. Small differences are common, because some employers divide by 52.14 weeks or by the number of working days in the year instead.
Frequently asked questions
What does pro rata mean on a job advert?
It means the salary shown is for full-time hours, and you will be paid a proportion of it based on the hours you work.
How do I calculate pro rata for 3 days a week?
If full time is 5 days, 3 days is 60%. Multiply the full-time salary by 0.6.
Is holiday pro rata as well?
Yes. Statutory holiday of 5.6 weeks is calculated pro rata for part-time workers, and contractual holiday usually is too.
Why is my term-time salary higher than the calculator shows?
Many employers add paid holiday to the weeks you work before calculating the fraction, which gives a higher figure than a simple weeks ÷ 52.
Sources
- GOV.UK: Part-time workers’ rights
- GOV.UK: Holiday entitlement
- GOV.UK: National Minimum Wage and National Living Wage rates
- GOV.UK: Income Tax rates and Personal Allowances
Rates for tax year 2026/27, last reviewed October 2026.
Results are estimates for planning, not financial or tax advice. See our terms and methodology.