The short version: Pro rata means proportional. If you work part time, your salary is pro rata of the full time equivalent. If you start mid month, your first pay is pro rata for the days worked.
How do you calculate it?
Work out the full amount, then multiply by the fraction that applies. A £30,000 full time salary at 20 hours a week instead of 40 is £15,000 pro rata. Three weeks of a £2,000 monthly salary is roughly £1,500.
Where does it come up?
Part time work, starting or leaving mid period, seasonal employment, calculating benefits that depend on time served, working out pension contributions, and dividing shared costs.
Does it affect tax?
Your tax is calculated on your actual earnings, so if you’re paid pro rata, your tax will be proportional too. You still get the same Personal Allowance as a full time worker.
Watch out for job adverts
When a job lists a salary “pro rata”, they’re telling you the full time equivalent. If it says £40,000 pro rata for a three day week, you’d actually receive about £24,000.
Need help understanding your pay calculations? We can break it down for you.
