Pro Rata Salary Calculator UK: Part-Time Hours, Days and Holiday

Turn a full-time salary into the pay for your part-time hours or days, or for the part of the year you work. Say a job is advertised at £30,000 pro rata for a 37.5-hour week and you work 22.5 hours. That is 60% of full time, so you earn £18,000 a year, £1,500 a month or £346.15 a week, at the same £15.38 an hour as a full-timer. If you start in July and work 9 months of the year, the pay for that first year is £13,500.

How pro rata salary is worked out

Pro rata means in proportion. Your pay is the full-time equivalent (FTE) salary scaled by how much of a full-time week you work:

1. By hours: pro rata salary = full-time salary × your hours ÷ full-time hours.
2. By days: pro rata salary = full-time salary × your days ÷ full-time days. Use this when your days are the same length as a full-timer’s.
3. Part of the year: multiply the yearly figure by the months you work ÷ 12, or by the calendar days you are employed ÷ 365.
4. Hourly or daily rate: full-time salary ÷ (full-time hours or days × 52). It is the same for everyone doing the job.

The monthly figure is the yearly pay divided by 12 and the weekly figure is the yearly pay divided by 52, which is how most UK payrolls convert a salary. If you leave or join part way through a month, your employer may instead pay you for the working days or calendar days in that month, so your first and last payslips can differ slightly from these figures.

Your rights as a part-time worker

Under the Part-time Workers (Prevention of Less Favourable Treatment) Regulations 2000, a part-time worker must not be treated less favourably than a comparable full-timer just because they work part time, unless the employer can objectively justify it. In practice that means:

• the same hourly rate of pay, including sick pay and family leave pay;
• the same access to the pension scheme, training, promotion and career breaks;
• benefits such as bonuses and holiday given pro rata. GOV.UK’s example: if full-timers get a £1,000 Christmas bonus, someone working half the hours should get £500;
• overtime rates may not start until you have worked more than the normal full-time hours.

There is no legal number of hours that makes a job full time, although GOV.UK notes that full-time workers usually work 35 hours or more a week. Whatever the hours, your pay must not fall below the National Minimum Wage for your age, which is £12.71 an hour from age 21 from 1 April 2026.

Holiday for part-time workers

Almost every worker is entitled to 5.6 weeks of paid holiday a year. For a full-timer on a 5-day week that is 28 days, and for part-timers it is worked out the same way:

Bank holidays do not have to be given as paid days off, but an employer can count them as part of the 5.6 weeks. Many contracts give more than the minimum, and part-timers should then get the extra pro rata too. For irregular-hours or part-year workers, holiday builds up based on the hours actually worked.

Things to check

• Read the advert carefully: “£30,000 pro rata” is the full-time figure, not what you will be paid.
• Check what the employer counts as a full-time week. A 35-hour week and a 40-hour week give different results for the same salary.
• Lower pay can change your tax and National Insurance. In 2026/27 you pay no Income Tax on the first £12,570 and no employee National Insurance below £12,570 a year.
• Ask whether paid breaks, on-call time or training count as working hours in your contract.

FAQs

What does pro rata mean in a job advert?

It means the salary shown is for full-time hours and you will be paid a proportion of it. A job at £24,000 pro rata for 20 hours, where full time is 40 hours, pays £12,000 a year.

Is pro rata pay worked out on 52 weeks?

Usually yes. Annual salaries are normally divided by 12 for monthly pay and by 52 for weekly pay, with paid holiday included in the year. Some employers work out a daily rate using working days in the year (for example 260), so check your contract if your start or leaving date falls mid-month.

Do part-time workers get paid bank holidays?

There is no automatic right to bank holidays off with pay. Your statutory 5.6 weeks can include them, and if your employer gives full-timers bank holidays on top of their leave, part-timers should get a pro rata equivalent so they are not treated less favourably.

Can I be paid less per hour for working part time?

Not just because you are part time. You can complain to your employer in writing and ask for a written statement of reasons, which they must give within 21 days. You may then be able to go to an employment tribunal.

Related calculators

• Holiday Entitlement CalculatorStatutory leave in days or hours
• Take-Home Pay Calculator 2026/27What your pro rata salary is after tax and NI
• Hourly to Salary Calculator UKConvert hourly, weekly and yearly pay

Sources

• GOV.UK: Part-time workers’ rights
• legislation.gov.uk: Part-time Workers Regulations 2000, regulation 5
• GOV.UK: Holiday entitlement · 5.6 weeks, 28-day cap
• GOV.UK: National Minimum Wage and National Living Wage rates · from 1 April 2026
• GOV.UK: Rates and thresholds for employers 2026 to 2027