What Is a Pro Rata Salary?

Pro rata is Latin for “in proportion”, and in a job advert it means the salary shown is the full-time figure, and you will receive the share of it that matches your hours.

The calculation

Full-time salary × your hours ÷ full-time hours.

For a 32,000 role where full-time is 37.5 hours and you will work 22.5:

32,000 × 22.5 ÷ 37.5 = 19,200 a year.

For a role expressed in days, the same idea: 30,000 for three days a week where full-time is five is 30,000 × 3 ÷ 5 = 18,000.

The hourly rate does not change. 32,000 for 37.5 hours is 16.41 an hour; 19,200 for 22.5 hours is also 16.41 an hour. If your pro rata offer implies a lower hourly rate than the full-time one, something is wrong.

What else scales

Holiday. Full-time entitlement multiplied by the same fraction. Twenty-eight days at 3/5 is 16.8, rounded up to 17. For irregular hours, calculate in hours rather than days.

Pension contributions. Both yours and the employer’s are percentages of salary, so they scale automatically.

Sick pay, parental pay, bonuses. Usually pro rata where they are expressed as amounts; unchanged where they are percentages.

Benefits in kind such as private healthcare are often provided in full regardless of hours, though employers can pro rata them if the scheme allows.

Term-time only

A specific and confusing case. A school-based role might be advertised at a full-time salary “pro rata, term-time only”. Here two reductions apply: one for hours per week if the role is part-time, and one for weeks per year, since you are paid for term weeks plus a holiday allowance rather than all 52.

A common formula is to pay for the working weeks plus the statutory holiday equivalent, which for 39 term weeks comes to around 43 to 45 paid weeks out of 52. So a 25,000 full-time salary, full-time hours but term-time only, might pay around 21,500. Always ask for the calculation in writing.

Reading an advert

“30,000 pro rata” for a 20-hour role, without stating full-time hours, is incomplete. Full-time might be 35 or 40, and the answer differs by 14 percent. Ask what the full-time hours are before comparing offers.

“30,000 FTE” means the same thing: full-time equivalent.

Monthly pay

Divide the pro rata annual figure by 12. For 19,200 that is 1,600 a month before tax. Tax and National Insurance are then calculated on the actual amount received, so the personal allowance covers a larger share of a part-time salary and the effective tax rate is lower than on the full-time figure.

Checking an offer

Ask for three numbers: the full-time salary, the full-time hours, and your hours. Multiply the first by the third and divide by the second. If the offer letter shows something different, ask why before signing.