Pro rata calculator
A pro rata salary is the full-time pay scaled to the hours you actually work: full-time salary × your hours ÷ full-time hours. That is the same sum as a part time salary calculation, and the same one a term time contract uses, so this answers what is pro rata in practice, and works as a part time pay calculator, a pro rata wage and prorated salary calculator, and a full-time equivalent (FTE) calculator, the whole time equivalent (WTE) sum the NHS uses by that name too. It is not the right tool for a term time only contract, where the weeks you are paid for matter as much as the hours: the term time only salary calculator does that one. Enter both figures and it shows the pro rata amount, and, unlike most, what it comes to after tax, which is not simply scaled down.
Calculator
Pro rata and part time calculator
2026/27 rates, checked 28 August 2026. Assumes the standard 1257L tax code, no pension and no student loan.
Working 22.5 of 37.5 hours (60% of full time)
£18,000 a year
£16,479.60 take-home, £1,373.30 a month
Full-time vs your hours
Tax is not pro-rated. Your personal allowance stays £12,570.00 however few hours you work, so part-time pay is taxed more lightly per pound.
| Full-time | Your hours | |
|---|---|---|
| Gross salary | £30,000.00 | £18,000.00 |
| Income tax | −£3,486.00 | −£1,086.00 |
| National Insurance | −£1,394.40 | −£434.40 |
| Take-home | £25,119.60 | £16,479.60 |
| Monthly take-home | £2,093.30 | £1,373.30 |
| You keep | 83.7% | 91.6% |
You earn 60% of the full-time salary but keep 66% of the full-time take-home, the difference is the allowance working harder for you.
How pro rata pay is worked out
A job advertised at “£30,000 pro rata” pays £30,000 only for full-time hours, usually 37.5 a week, sometimes 35 or 40. Work 22.5 hours (three days) against a 37.5-hour full-time week and you are paid 60% of it: £18,000 a year. The same scaling applies whether the arrangement is fewer hours per day, fewer days per week, or a job share.
Statutory holiday scales the same way: the 5.6-week minimum becomes 5.6 weeks of your working week, so a three-day week carries 16.8 days rather than 28.
Why part-time pay is taxed more lightly
Your salary is pro-rated; your tax-free personal allowance is not. It stays £12,570.00 whether you work five days or two. On the £18,000 example, the allowance shelters 70% of pay rather than 42%, so the part-timer keeps £16,479.60 of £18,000, 91.6% of gross, against 83.7% for the full-timer. National Insurance behaves the same way, because its £12,570 threshold is not pro-rated either.
The practical consequence: dropping from five days to four costs less take-home than one-fifth. The days you give up are your most heavily taxed pounds.
What this calculator assumes
- The standard 1257L tax code, and that this is your only job.
- Pay spread evenly across the year. Term-time-only contracts are annualised — the shape of that formula is explained below.
- No pension or student loan, add those on the main calculator with your pro rata figure.
Dropping a day rather than changing your hours generally is the same arithmetic with a different question attached, and the answer surprises people: you give up a fifth of your gross salary but less than a fifth of your take-home. The four-day week calculator prices the day off against what a working day actually earns you.
What does pro rata mean?
Pro rata means “in proportion”: a £30,000 pro rata salary pays £30,000 only for full-time hours, scaled down to the share of those hours you actually work. Against a 37.5-hour full-time week, 30 hours is 80% of the job and pays 80% of the salary — £24,000 a year.
Pro rata holiday entitlement
The statutory minimum is 5.6 weeks of your working week: multiply 5.6 by the days you work. Three days a week is 5.6 × 3 = 16.8 days of paid holiday, against 28 days (the statutory cap) for a five-day week.
| Days worked a week | Statutory minimum holiday |
|---|---|
| 5 | 28 days |
| 4 | 22.4 days |
| 3 | 16.8 days |
| 2 | 11.2 days |
Bank holidays are not an extra right on top: your employer can count them within the 5.6 weeks, and a part-timer’s allowance must be pro-rated fairly even if none of their working days fall on a bank holiday.
Source: gov.uk holiday entitlement rights, checked 2 September 2026.
Term-time-only contracts
Term-time-only pay is annualised: you are paid for the weeks you work plus your statutory holiday, spread over twelve equal monthly instalments. The usual shape is (weeks worked + holiday weeks) ÷ 52.14 × the pro rata salary, where 52.14 is the number of weeks in a year. On a £18,000 pro rata salary for 39 working weeks plus 5.6 weeks’ holiday, that is 44.6 ÷ 52.14 = 85.5%, about £15,397 a year before tax. Employers’ formulas vary — some divide by 52, or use a holiday figure above the statutory 5.6 weeks — so check the divisor in your contract before relying on the result.
Source: statutory 5.6-week holiday figure from gov.uk holiday entitlement rights, checked 2 September 2026.
2026/27 HMRC rates, checked 28 August 2026 by Hadi. Sources and method on the about page.
How to use the pro rata calculator
- 1
Enter the full-time salary from the advert, the figure quoted before the words “pro rata”.
- 2
Set the full-time week the employer uses, usually 37.5 hours, sometimes 35 or 40.
- 3
Enter the hours or days you will actually work, or switch to term-time if your contract is annualised.
- 4
Read the pro rata salary and, below it, what lands in your bank after income tax and National Insurance.
When should you use the pro rata calculator?
Use it whenever a salary is quoted for full-time hours you will not be working, whether that is part time, a job share or term time only.
A job advert says “£30,000 pro rata”
The advert quotes the full-time rate. You need the scaled figure before deciding whether the job pays enough.
Cutting your hours
Your salary scales down but your tax-free allowance does not, so you keep a larger share of a smaller salary.
You work term time only
School and college contracts are annualised over twelve months, and the divisor in your contract changes the answer.
Checking a job share
Two people splitting one full-time post are each paid their share of the same full-time salary.
Where to go next
- 4 day week calculatorTo price a single day off against what that day really earns.Open
- Hourly wage calculatorTo start from an hourly rate instead of a salary.Open
- Minimum wage calculatorTo check the reduced hours still clear the legal minimum.Open
All 51 calculators share one tested engine, so a figure from the pro rata and part time calculator agrees with every other page here. See the full calculator index or the pay and tax guides.