Pro-rata salary calculator

What a full-time salary works out at on reduced hours — and, the other way round, what a part-time salary is worth full-time.

A job advert saying “£35,000 pro rata” is quoting the full-time figure. What you would be paid depends on the hours, and the advert often does not say what full time means there. This works out both.

The advertised or current figure, before tax.

What full time means where you work. Check the contract.

The short version

What pro rata means
In proportion. A pro-rata salary is the full-time figure scaled to the hours actually worked.
What full time means
There is no legal definition. Most UK employers use 35 to 40 hours; the figure in the contract is what counts.
Holiday scales too
5.6 weeks of your own working week. Three days a week gives 16.8 days, not 28.
Tax does not scale
Half the salary is less than half the tax, because the personal allowance is the same either way.
Part-time rights
Part-time workers must not be treated less favourably than comparable full-time colleagues, under the 2000 Regulations.

Common questions

What does "£35,000 pro rata" mean in a job advert?

It means £35,000 is the full-time salary and you will be paid the share of it that matches your hours. If full time is 37.5 hours and the role is 22.5, that is £21,000. Adverts often leave out what full time means there, which is worth asking before you apply.

How many hours is full time in the UK?

There is no legal definition. Most employers use somewhere between 35 and 40 hours a week, and the figure in your contract is the one that matters for this calculation. The 48-hour limit in the Working Time Regulations is a maximum, not a definition of full time.

Is my holiday pro rata as well?

Yes, but scaled to your own working week rather than to a day count. You get 5.6 weeks of whatever week you work, so three days a week is 16.8 days rather than 28. The 28-day cap only bites at five days a week or more.

Will I pay half the tax on half the salary?

No, less than half. The personal allowance is the same whatever your hours, so a smaller share of your pay is taxed at all. Someone on half a salary usually keeps a higher percentage of it.

Can I be paid a lower hourly rate for working part time?

Not for the same work. The Part-time Workers Regulations 2000 make it unlawful to treat a part-time worker less favourably than a comparable full-time colleague without objective justification, and that includes the hourly rate.

Does a pro-rata salary affect my pension?

Contributions usually scale with pay, so a lower salary means lower contributions from both sides. Whether you are automatically enrolled at all depends on your earnings passing the trigger, which some part-time roles do not.

What the terms mean

Pro rata
Latin for "in proportion". Applied to salary, it means the full-time figure scaled by the share of full-time hours worked.
Full-time equivalent (FTE)
A part-time role expressed as a share of full time. Someone working 18.75 hours where full time is 37.5 is 0.5 FTE.
Comparable full-time worker
A colleague on the same type of contract doing broadly similar work. The comparison that decides whether part-time treatment is less favourable.
Annualised hours
A contract setting hours across the year rather than the week, common in term-time and seasonal work. The pro-rata share is calculated over the year.

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Figures on this page are checked against primary sources and dated. They are not legal, tax or financial advice.

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