"£35,000 pro rata, three days a week." The ad looks generous until you do the arithmetic, and the arithmetic is what "pro rata" is asking you to do. It is a term searched overwhelmingly at one precise moment: when someone is holding a job advert and trying to work out what actually lands in the bank.
The definition in one line: pro rata means "in proportion": a salary, holiday allowance or benefit scaled to the time actually worked. A £35,000 pro rata salary at three days a week pays three-fifths of £35,000. That is the whole mechanism. What follows is the formula, worked examples using the numbers people actually search for, the holiday rule that catches everyone out, and how to compare a part-time offer against a full-time one without fooling yourself.
TL;DR. Pro rata means "in proportion": pay and benefits scaled to hours worked. Annual salary ÷ full-time hours × your hours gives the pro rata salary: £35,000 at three days a week is £21,000. Holiday entitlement is prorated the same way from the statutory 5.6 weeks full-time equivalent. To compare offers, always normalise both to a per-day figure first.
What does pro rata mean on a job advert?
When a UK advert shows "£35,000 pro rata", the £35,000 is the full-time equivalent (FTE) salary, and the word pro rata is the disclaimer that you will receive the proportion matching your working pattern. The same logic covers the rest of the package: holiday, pension contributions, and sometimes bonuses, each scaled to the hours worked unless the contract says otherwise.
The term appears wherever part-time, term-time, job-share and fractional roles are advertised: from teaching assistants (the classic UK pro rata profession) to fractional specialists in tech and finance. It also appears outside salary: rent charged pro rata for a partial month, refunds calculated pro rata for unused service. Same principle every time: the full amount multiplied by the fraction of time or use.
How to work out a pro rata salary
The formula, with full time taken as five days a week:
Pro rata salary = FTE salary ÷ 5 × days worked per week (or, working in hours: FTE salary ÷ full-time hours × your contracted hours)
Two worked examples, using the figures people search for most:
| FTE salary | Working pattern | Fraction | Actual pay |
|---|---|---|---|
| £35,000 | 3 days a week | 3/5 | £21,000 |
| £35,000 | 4 days a week | 4/5 | £28,000 |
| £25,000 | 3 days a week | 3/5 | £15,000 |
| £25,000 | 2.5 days a week | 1/2 | £12,500 |
For hourly precision, use hours instead of days: a 37.5-hour week makes £35,000 equivalent to about £18 an hour (£35,000 ÷ 52.14 weeks ÷ 37.5 hours); multiply by your contracted hours. Employers must apply at least the pro rata principle to the national minimum wage: a part-timer's hourly rate cannot fall below the floor just because the salary headline looks healthy.
How many hours is pro rata?
Pro rata is a proportion, not a number of hours, but in UK practice the denominator is the company's full-time week, typically 37.5 or 40 hours across five days. A "pro rata, 22.5 hours" role at a 37.5-hour company is three days; the same 22.5 hours at a 40-hour company is 56% of full time. When an advert gives only the fraction ("0.6 FTE"), multiply the full-time salary and the full-time hours by 0.6 and you have the whole picture.
How does pro rata holiday work in the UK?
Holiday is where pro rata surprises people. The statutory minimum for a full-time worker is 5.6 weeks a year: 28 days if bank holidays are included in the count. Part-timers get the same 5.6 weeks of their working week, calculated as the FTE allowance × days worked: three days a week earns 16.8 days a year. Crucially, part-time workers cannot be treated worse than full-timers pro rata: a company giving full-timers 33 days must give a three-day worker 19.8, not the bare statutory 16.8.
The same scaling applies to accruing holiday during maternity or parental leave and to pay in lieu of untaken leave when a contract ends. If a payroll shows something that looks like short change, the arithmetic to check first is the fraction: allowances divided by five, times the days worked.
Comparing a pro rata offer with a full-time salary
The mistake almost everyone makes: comparing a pro rata headline with a full-time headline as if they were the same currency. The honest comparison normalises both to a per-day rate. £21,000 for three days is £140 a day; a £32,000 full-time role is £123 a day at 260 working days. The "smaller" part-time job actually pays better per day, which matters if a fourth day is negotiable later.
Three more things to normalise before signing. Pension: employer contributions usually apply to actual earnings, so a pro rata role builds a proportionally smaller pot. Progression: check whether the pro rata salary band is the same band as the full-time equivalent role. And benefits with fixed costs (private health cover, gym, travel loans) are sometimes not prorated at all, which quietly changes the value of the whole package for a three-day week.
For companies, the same arithmetic runs in reverse, and it is the reason the fractional model has grown in UK tech and marketing: a fractional specialist at three days a week delivers senior capability at 0.6 of the senior cost, the logic behind hiring experienced project managers or data leads for the days the work actually needs. Mid-sized companies driving transformation with lean teams work this way with Shakers, and specialist profiles such as a fractional data scientist follow the same pattern.
- What is 35,000 pro rata salary?
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£35,000 is the full-time equivalent, and your actual pay is that figure scaled to your hours. At three days a week it is £21,000 a year (£35,000 × 3/5); at four days, £28,000. The formula is FTE salary ÷ 5 × days worked.
- How many hours is pro rata?
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Pro rata itself is a proportion, not an hour count. In the UK the proportion is taken against the employer's full-time week, usually 37.5 or 40 hours over five days. A pro rata role of 22.5 hours is three days at a 37.5-hour company, or 56% of full time at a 40-hour one.
- What does pro rata mean legally?
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Legally, part-time workers must not be treated less favourably than comparable full-timers: pay, holiday and most conditions scale pro rata, and the hourly rate must still meet the national minimum wage. Statutory holiday is 5.6 weeks of the working week, so a three-day worker is entitled to 16.8 days a year, and any enhanced full-time allowance must be prorated too.
- How do you calculate pro rata holiday?
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Take the full-time annual allowance including bank holidays (28 days is the statutory minimum) and multiply by the days worked per week divided by five. Three days a week: 28 × 0.6 = 16.8 days. If the employer gives full-timers more than the statutory minimum, part-timers get that enhanced figure prorated, not the bare minimum.
