Pro Rata Salary Calculator

How the pro rata salary calculator works

1. 1

   Enter the advertised full-time salary

   Job adverts that say a salary is pro rata are quoting the full-time equivalent. Enter that headline figure first, because everything else is a proportion of it rather than a separate rate of pay.

2. 2

   Enter the employer's full-time hours

   Full-time hours vary by employer, commonly between 35 and 40 hours a week. The same part-time hours produce a different pro rata salary depending on what the employer counts as full time, so use their figure rather than a general assumption.

3. 3

   Enter the hours you actually work

   The ratio between your hours and full-time hours is the proportion of the salary you receive. The calculator shows this proportion explicitly so you can sanity-check an offer against the advertised figure.

4. 4

   Add a part-year period if you are not working the full year

   If you are joining, leaving or working a fixed-term contract partway through the year, set the number of months. The calculator then shows both the annualised salary and the amount for that shorter period.

The pro rata salary formula

Pro rata annual salary = full-time salary x (your hours / full-time hours) Part-year pay = pro rata annual salary x (months worked / 12)

• •The hours ratio and the part-year ratio are applied separately, so a half-time role for six months pays a quarter of the full-time annual salary.
• •The monthly figure is the pro rata annual salary divided by twelve and the weekly figure divides it by 52, which is how most UK employers express part-time pay.
• •Pro rata scaling applies to salary. Holiday entitlement, pension contributions and statutory payments each have their own rules and are not simply the same percentage.
• •This calculator works in gross pay. Income Tax and National Insurance are deducted from the pro rata figure, not from the full-time equivalent.

Worked example: three days a week on a £35,000 full-time salary

A role is advertised at £35,000 a year pro rata, based on a 37.5-hour full-time week. The successful candidate will work 22.5 hours a week, spread across three days, for the whole year.

Full-time salary

£35,000

Full-time hours per week

37.5

Hours actually worked per week

22.5

Proportion of full time

60%

Pro rata annual salary

£21,000.00

Monthly gross pay

£1,750.00

Weekly gross pay

£403.85

The role pays £21,000 a year, which is 60% of the £35,000 full-time equivalent salary.

What pro rata does and does not cover

Pro rata is about proportion, not a lower rate of pay

A pro rata salary should represent the same hourly value as the full-time equivalent. If the implied hourly rate is lower than a full-time colleague doing the same job, that is a pay question rather than a pro rata calculation.

Holiday is pro-rated by weeks, not by salary percentage

Statutory holiday is 5.6 weeks of your own working pattern. Someone working three days a week gets 16.8 days rather than 60% of a 28-day allowance applied to a five-day pattern, so use a holiday entitlement calculator for leave.

Benefits and pensions follow their own rules

Pension contributions are usually a percentage of actual pay, but auto-enrolment qualifying earnings thresholds are not pro-rated. Some benefits are all-or-nothing regardless of hours, so check the scheme rules.

Part-year and part-time are separate reductions

Working reduced hours for part of a year applies both reductions. The calculator keeps them visible so you can see whether an offer reflects the hours, the period, or both.

Frequently asked questions

What does pro rata mean on a job advert?

It means the salary shown is the full-time equivalent and your actual pay will be a proportion of it based on the hours you work. A £35,000 pro rata salary for a role you do at three days a week on a 37.5-hour full-time pattern pays £21,000. The advert quotes the full-time figure so that candidates on different hours can compare the role on a like-for-like basis.

How do I work out my pro rata salary?

Divide your weekly hours by the employer's full-time weekly hours, then multiply the full-time salary by that fraction. For 22.5 hours against a 37.5-hour week the fraction is 0.6, so a £35,000 salary becomes £21,000. If you are also only working part of the year, multiply again by the months worked divided by twelve.

Does full-time mean the same number of hours everywhere?

No, and it materially changes the answer. Full time is commonly anywhere between 35 and 40 hours a week in the UK, and there is no single statutory definition. Twenty-two and a half hours is 64% of a 35-hour week but only 56% of a 40-hour week, so always use the employer's own full-time hours when checking a pro rata figure.

Is my holiday entitlement also 60% if I work 60% of full-time hours?

Not in the way most people expect. Statutory holiday is 5.6 weeks of your own working pattern, so a three-day-a-week worker is entitled to 16.8 days rather than a percentage of a 28-day full-time allowance. The result often looks similar, but the calculation is different and the difference matters when bank holidays are included in the allowance.

Is a pro rata salary calculated before or after tax?

Before. The pro rata figure is your gross salary, and Income Tax, National Insurance, student loan repayments and pension contributions are then deducted from that reduced amount. Because the Personal Allowance is not pro-rated, part-time workers often pay proportionally less tax than the headline full-time salary would suggest.