Last reviewed: February 2026 by Mustafa Bilgic, UK Tax Specialist
Pro Rata Salary Calculator
What is Pro Rata Salary?
Pro rata is a Latin term meaning "in proportion". In the context of employment, a pro rata salary is the salary you would earn for the portion of a full working week or year that you actually work. It is the fairest and most common way to pay part-time, job-share, term-time, and temporary workers in the UK.
The Core Formula
Pro Rata Salary Formula
By hours: Pro Rata Salary = (Your hours per week ÷ Full-time hours per week) × Full-time annual salary
By days: Pro Rata Salary = (Your days per week ÷ 5) × Full-time annual salary
Example: Full-time salary £30,000, standard hours 37.5/week. Part-timer works 22.5 hours/week:
(22.5 ÷ 37.5) × £30,000 = 0.6 × £30,000 = £18,000 pro rata salary
Common Pro Rata Working Patterns
3-Day Week (60%)
On £30,000 FTE: (3÷5) × 30,000 = £18,000 pro rata
4-Day Week (80%)
On £30,000 FTE: (4÷5) × 30,000 = £24,000 pro rata
Half-Time (50%)
On £30,000 FTE: 0.5 × 30,000 = £15,000 pro rata
Term-Time (75%)
39/52 weeks: on £30,000 FTE = £22,500 (simple method)
Term-Time Working: How Pro Rata is Calculated
Term-time workers — such as teaching assistants, school administrators, and lunchtime supervisors — typically work during the 39 school weeks per year but are contracted for the full year. Their salary is pro-rated accordingly.
Simple Method
Simple formula: (Weeks worked ÷ 52) × FTE salary. For 39 weeks: (39 ÷ 52) × £28,000 = £21,000.
Holiday-Adjusted Method (More Accurate)
This method accounts for the fact that part of the "non-working" period includes holiday entitlement that is earned and taken during the non-term period.
- Calculate annual hours: 39 weeks × hours/week
- Add pro-rata holiday hours: statutory 5.6 weeks × (hours/week × 39/52)
- Multiply total hours by hourly rate from FTE salary
The holiday-adjusted salary is typically slightly higher than the simple method because it explicitly includes holiday pay within the calculation period.
Term-Time Example: 39 Weeks, £28,000 FTE, 37.5 hrs/week
Simple method: (39/52) × £28,000 = £21,000
Hourly rate from FTE: £28,000 ÷ (37.5 × 52) = £14.36/hr
Annual term-time hours: 39 × 37.5 = 1,462.5 hours
Pro-rata holiday (5.6 wks × 39/52 × 37.5): 99.75 hours
Total paid hours: 1,562.25 hours
Salary: 1,562.25 × £14.36 = £22,434 (holiday-adjusted)
Pro Rata Holiday Entitlement
Part-time workers are legally entitled to the same proportion of annual leave as full-time workers. The statutory minimum in the UK is 5.6 weeks per year (28 days for 5-day workers, including bank holidays).
Calculating Pro Rata Holiday
Holiday entitlement for part-timers = 5.6 weeks × days/hours worked per week. For a 3-day week: 5.6 × 3 = 16.8 days. For a 22.5-hour week: 5.6 × 22.5 = 126 hours.
Bank Holidays Pro Rata
Bank holidays are often included within the 5.6 weeks' statutory entitlement. Part-time workers who do not normally work on the day a bank holiday falls should not lose holiday entitlement — their employer should offer an alternative day off or payment in lieu.
| Working Days/Week | FTE % | Holiday (Days/Year) | Holiday (inc. BH) |
|---|---|---|---|
| 5 days (full-time) | 100% | 28 days | 28 days |
| 4 days | 80% | 22.4 days | 22.4 days |
| 3 days | 60% | 16.8 days | 16.8 days |
| 2.5 days | 50% | 14 days | 14 days |
| 2 days | 40% | 11.2 days | 11.2 days |
Hourly Rate from Annual Salary
To find the implied hourly rate from a salary: Hourly rate = Annual salary ÷ (Hours per week × 52). This is useful for checking that a pro-rata salary meets the National Minimum Wage and for comparing roles with different working patterns.
| Annual Salary | 37.5 hrs/week | 35 hrs/week | 30 hrs/week | 25 hrs/week |
|---|---|---|---|---|
| £20,000 | £10.26/hr | £10.99/hr | £12.82/hr | £15.38/hr |
| £25,000 | £12.82/hr | £13.74/hr | £16.03/hr | £19.23/hr |
| £30,000 | £15.38/hr | £16.48/hr | £19.23/hr | £23.08/hr |
| £35,000 | £17.95/hr | £19.23/hr | £22.44/hr | £26.92/hr |
| £40,000 | £20.51/hr | £21.98/hr | £25.64/hr | £30.77/hr |
National Living Wage 2025/26: £12.21/hr (aged 21+). Any salary below £12.21/hr is unlawful.
How Pro Rata Salaries Work in the UK
Pro Rata salaries in the UK vary depending on experience, location, qualifications, and the specific employer. This calculator uses current 2025/26 HMRC tax bands and National Insurance rates to estimate your actual take-home pay after all statutory deductions.
Your gross salary is reduced by income tax (20% basic rate on earnings between £12,570 and £50,270, 40% higher rate above that) and National Insurance contributions (8% on earnings between £12,570 and £50,270, then 2% above). Pension contributions further reduce your taxable income if paid via salary sacrifice.
Key Information for 2025/26
The personal allowance remains frozen at £12,570, meaning no tax is due on the first £12,570 of annual earnings. The basic rate band extends to £50,270, and the higher rate band covers income from £50,271 to £125,140. Above £100,000, the personal allowance tapers by £1 for every £2 earned, creating an effective 60% marginal rate between £100,000 and £125,140.
Example Calculation
A pro rata earning £45,000 per year would pay £6,486 in income tax and £2,594 in National Insurance, resulting in take-home pay of approximately £35,920 per year or £2,993 per month. With a 5% pension contribution via salary sacrifice, the annual take-home drops to £34,300 but the pension pot gains £2,250 at a net cost of only £1,620.
Source: Based on official HMRC 2025/26 tax rates and thresholds. Last updated March 2026.
Frequently Asked Questions
What does pro rata salary mean?
Pro rata means "in proportion." A pro rata salary is a full-time equivalent (FTE) salary scaled down to reflect the actual hours or days worked. It ensures part-time workers are paid fairly relative to full-time colleagues doing the same role. In the UK, all employment rights — including pay, holiday, and pension — must be provided on a pro rata basis for part-time workers under the Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000.
How do I calculate my pro rata salary from full-time pay?
Use the formula: Pro Rata Salary = (Your hours ÷ Full-time hours) × Full-time salary. For a 30-hour week on a £36,000 FTE salary (37.5 hours): (30 ÷ 37.5) × £36,000 = 0.8 × £36,000 = £28,800. For days: (4 days ÷ 5 days) × £36,000 = £28,800. Both give the same result if a working day is 7.5 hours (37.5 ÷ 5).
How is pro rata salary calculated for term-time working?
The simple method: (weeks worked ÷ 52) × FTE salary. For 39 school weeks on a £28,000 FTE: (39 ÷ 52) × 28,000 = £21,000. The holiday-adjusted method (recommended by the Department for Education) accounts for the fact that holiday entitlement is built into the non-working weeks. This typically yields a slightly higher salary — around £22,000–£23,000 for the same FTE, depending on hours worked.
Am I entitled to the same holiday allowance on a pro rata basis?
Yes. Under UK law, part-time workers must receive the same proportion of annual leave entitlement as full-time workers. The statutory minimum 5.6 weeks (28 days for full-timers) is pro-rated by your working week.
A 3-day week worker gets 5.6 × 3 = 16.8 days/year. You cannot be treated less favourably in holiday entitlement simply because you work part-time.
How do I work out my hourly rate from an annual salary?
Hourly rate = Annual salary ÷ (Hours per week × 52). For £30,000 at 37.5 hours/week: £30,000 ÷ (37.5 × 52) = £30,000 ÷ 1,950 = £15.38/hour. This rate allows you to cross-check that any pro-rata salary meets the National Living Wage (£12.21/hour in 2025/26 for workers aged 21+) and to compare different job offers on an equivalent basis.
Can my employer pay me less than minimum wage on a pro rata basis?
No. The National Minimum Wage applies to every hour worked, regardless of the working pattern. In 2025/26: £12.21/hour (aged 21+), £10.00/hour (aged 18–20), £7.55/hour (under 18), £7.55/hour (apprentices in first year or under 19). If your hourly rate — calculated from your pro rata annual salary and actual hours — falls below these thresholds, your employer is breaking the law and you can report them to HMRC.
What is a full-time equivalent (FTE) salary?
FTE salary is the notional salary for working full-time hours (usually 37.5 or 40 hours/week). Job adverts often state "£X pro rata" — this means X is the FTE figure and your actual salary will be reduced proportionally. To find your FTE from your actual salary: FTE = (Actual salary ÷ Actual hours) × Full-time hours. Example: £20,000 for 25 hours/week → FTE = (£20,000 ÷ 25) × 37.5 = £30,000.