Pro Rata Salary Calculator 2025/26
Calculate a pro rata salary for any situation — a mid-year starter or leaver, a part-time employee on reduced hours, or converting an annual salary to a daily or hourly rate. Includes take-home pay after income tax and NI.
How pro rata salary is calculated
Part-year (start/leave date): The most common method is to divide the annual salary by 52.18 (the average number of weeks in a year) and multiply by the number of working weeks in the period. Some employers use calendar days (÷ 365 × days worked) or whole months (÷ 12 × months worked). All methods are legally valid; your contract or staff handbook should specify which applies.
Part-time: Simply divide your contracted hours by the full-time equivalent hours and multiply by the FTE salary. Equal treatment legislation means part-time workers must receive the same hourly pay and benefits (holiday entitlement, pension, sick pay) as full-time colleagues doing equivalent work.
Part-time workers are entitled to 5.6 weeks’ holiday per year, pro rated to their contracted hours. For someone working 3 days a week, that’s 3 × 5.6 = 16.8 days. This must include bank holidays, which are similarly prorated — part-timers who don’t normally work on bank holidays get a compensating day off instead.
