Pro-rata salaries are calculated according to what percentage of a full-time job your hours make up if you work part time [ie less than full-time hours]. For example, if you work two days a week and a full-time person in your position gets £18,000. You will get two fifths of that for a pro rata salary.
Some pro-rata salaries are fairly easy to work out: if you do three full days, you would just get three fifths of the full-time salary. However, if you work shorter days, you would need to work out your salary based on the percentage of full-time hours per week that you work.
The same goes for holidays. A part-time worker will get a pro rata of a full-time worker’s holiday entitlement. The minimum holiday entitlement for full-time workers is 28 days. This may or may not include bank holidays, but bank holidays do not have to be given as additional to the 28 days.