How to use the pro rata salary calculator
- Enter the full-time salary for the job, as advertised or in your contract, and the full-time hours a week. Many UK jobs use 37.5 hours; others use 35, 39 or 40. Use the figure for your employer.
- Enter your own pattern, either the hours you work a week or the days you work out of the full-time days.
- Optional: add the first and last day if you only work part of the year, and choose an age group to check the hourly rate against the National Minimum Wage.
The results update as you type. All figures are before tax, National Insurance, pension and any other deductions, so they will be higher than your take-home pay.
How pro rata salary is worked out
"Pro rata" means in proportion. A part-time salary is the full-time salary in proportion to the time you work:
- Full-time equivalent (FTE) = your hours ÷ full-time hours
- Pro rata salary = full-time salary × FTE
- Monthly = pro rata salary ÷ 12, weekly = pro rata salary ÷ 52
- Hourly rate = full-time salary ÷ (52 × full-time hours)
For example, a job paying £30,000 for 37.5 hours a week, where you work 22.5 hours:
| Step | Sum | Result |
|---|---|---|
| FTE | 22.5 ÷ 37.5 | 0.6 (60%) |
| Pro rata salary | £30,000 × 0.6 | £18,000.00 |
| A month | £18,000 ÷ 12 | £1,500.00 |
| A week | £18,000 ÷ 52 | £346.15 |
| An hour | £30,000 ÷ (52 × 37.5) | £15.38 |
Your hourly rate stays the same as a full-time colleague's. That is the point of pro rata pay: you are paid less in total only because you work fewer hours. GOV.UK says part-time workers should get the same treatment as full-time workers for "pay rates", and that some benefits are applied "'pro rata' (in proportion to hours worked)". Its own example: if a full-time worker gets a £1,000 bonus and a part-time worker works half the hours, "they should get £500".
Working it out by days instead of hours
If you work the same length of day as full-time staff, but fewer days, choose Days per week. Three days out of five is an FTE of 0.6, the same as 22.5 out of 37.5 hours. So £24,000 full-time becomes £14,400 for three days a week, or £1,200 a month.
If your days are shorter or longer than a full-time day, use hours instead, because days alone would give the wrong answer. Someone working three 6-hour days (18 hours) in a 37.5-hour job has an FTE of 0.48, not 0.6.
Starting or leaving part way through the year
Open Only part of the year? and enter your first and last day. The calculator takes your pro rata salary for a year and multiplies it by the calendar days in your dates, divided by 365 (or 366 when the dates include 29 February).
For example, £18,000 a year from 1 January to 30 June 2026 is 181 days: £18,000 × 181 ÷ 365 = £8,926.03. Employers do not all use the same method for a part month. Some count working days, or pay a set fraction per month, so your first or last payslip may differ by a few pounds. Your contract or payroll team can tell you which method they use.
Minimum wage check
Your hourly rate must not be below the National Minimum Wage for your age. These are the GOV.UK rates from April 2026:
| Age or status | Hourly rate |
|---|---|
| 21 and over (National Living Wage) | £12.71 |
| 18 to 20 | £10.85 |
| Under 18 | £8.00 |
| Apprentice | £8.00 |
GOV.UK notes that "The rates change on 1 April every year." The apprentice rate applies to apprentices aged under 19, or aged 19 or over and in the first year of their apprenticeship; after that they get the rate for their age.
Choose your age group under Minimum wage check and the calculator warns you if the hourly rate is lower. It is a quick check based on the salary and contracted hours, not the full minimum wage calculation. If the figures are close, check GOV.UK's guidance.
Holiday, overtime and other things to know
- Holiday is pro rata too. Part-time workers get at least 5.6 weeks of paid holiday, which is fewer days than full-time staff. Use the holiday entitlement calculator to work it out.
- Overtime. GOV.UK says part-time workers "may not get overtime pay until they've worked over the normal hours of a full-time worker."
- 52 weeks. A year is a little over 52 weeks, but salaries are usually divided by 52 for a weekly figure, and this calculator does the same.
Questions and answers
How do I calculate a pro rata salary?
Divide your hours by the full-time hours, then multiply the full-time salary by that number. 22.5 hours in a 37.5-hour job is 0.6, so a £30,000 salary becomes £18,000.
What does FTE mean?
Full-time equivalent. It is the share of a full-time job that you work. 1.0 is full time, 0.6 is three days out of five or 22.5 hours out of 37.5. Job adverts sometimes give a salary "FTE", which means the full-time figure before it is pro rata.
Is the pro rata salary before or after tax?
Before. The calculator shows gross pay. Income Tax, National Insurance and pension contributions come off it, depending on your tax code and pension scheme.
What are full-time hours in the UK?
There is no single legal number. GOV.UK says a full-time worker "will usually work 35 hours or more a week". Many jobs use 37.5 hours. Use the full-time hours your employer uses for the role.
Is my hourly rate lower if I work part time?
It should not be. Part-time workers should get the same pay rates as comparable full-time workers, so a pro rata hourly rate is the same as the full-time hourly rate.
Sources
Checked on 7 October 2026. If a rule has changed, please tell us.