Pro Rata Calculator
Calculate your proportional salary based on hours, days, or weeks worked
📊 Pro Rata Calculator
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How the Pro Rata Calculator Works
This pro rata calculator converts any full-time UK salary into its part-time equivalent instantly. Enter your full-time annual salary, the standard weekly hours for the role, and your actual contracted hours. The tool applies the standard pro rata formula used by UK employers and HR departments.
Pro rata means "in proportion" — the calculation divides salary proportionally based on hours worked versus full-time hours. The formula is: Pro Rata Salary = Full-Time Salary × (Your Hours ÷ Full-Time Hours). Results include annual, monthly, weekly, daily, and hourly breakdowns.
Who Needs a Pro Rata Calculator?
Part-time workers checking job offers, employees negotiating flexible working arrangements, HR professionals processing contracts, and parents returning to work on reduced hours all benefit from accurate pro rata calculations. With over 8.7 million part-time workers in the UK (ONS 2024), proportional salary calculation affects roughly one quarter of the workforce.
Our calculator also handles weeks-per-year adjustments for term-time workers and days-per-week variations, making it suitable for teachers, school support staff, and NHS employees on non-standard patterns.
Understanding Your Pro Rata Results
| Full-Time Salary | FT Hours | Your Hours | Pro Rata Annual | Monthly |
|---|---|---|---|---|
| £24,000 | 37.5 | 22.5 | £14,400 | £1,200 |
| £30,000 | 37.5 | 30 | £24,000 | £2,000 |
| £35,000 | 40 | 24 | £21,000 | £1,750 |
| £45,000 | 37.5 | 18.75 | £22,500 | £1,875 |
How to Use the Pro Rata Calculator
Using our pro rata calculator is straightforward. Follow these steps to get accurate results for your situation:
- Enter your full-time salary — This is the annual salary for the equivalent full-time role, before any deductions. You'll find this on the job advert or your contract.
- Set the full-time hours — The standard working week for the role. Most UK employers use 37.5 or 40 hours per week.
- Enter your actual hours — Your contracted weekly hours. This is the number you actually work.
- Click Calculate — The pro rata calculator displays your results instantly, with annual, monthly, weekly, daily, and hourly breakdowns.
Worked Example: Pro Rata Calculator
Let's work through a practical example of pro rata calculator. A marketing coordinator role advertises a full-time salary of £28,000 for 37.5 hours per week. You're offered the position at 25 hours per week.
Step 1 — Find your FTE ratio: 25 ÷ 37.5 = 0.667 (66.7%)
Step 2 — Calculate pro rata salary: £28,000 × 0.667 = £18,667 per year
Step 3 — Monthly breakdown: £18,667 ÷ 12 = £1,556 gross per month
Step 4 — Holiday entitlement: 28 days × 0.667 = 18.7 days pro rata
After income tax and NI (2025/26 rates), your monthly take-home would be approximately £1,377. Use our pro rata calculator above to check your own figures.
Tips for Using This Calculator
- Always use gross salary: Enter the salary before tax and deductions — the pro rata calculator works with gross figures.
- Check your contract: Your employment contract should state your full-time equivalent hours. Common UK standards are 35, 37, 37.5, and 40 hours per week.
- Know your rights: Under the Part-time Workers Regulations 2000, part-time employees must receive the same hourly rate, holiday entitlement (pro rata), and benefits as full-time colleagues.
- Tax personal allowance: For 2025/26, the first £12,570 of earnings is tax-free. If your pro rata salary falls below this, you pay no income tax at all.
- National Insurance: Employee NI is 8% on earnings between £12,570 and £50,270 (2025/26 rates). Check HMRC NI rates for the latest figures.
Pro Rata Holiday Entitlement
Under the Working Time Regulations 1998, all UK workers are entitled to a minimum of 5.6 weeks' paid holiday per year (28 days for full-time). If you work part-time, your entitlement is calculated pro rata based on your actual hours or days worked.
| Days Worked/Week | FTE Ratio | Statutory Days/Year | Bank Holidays (pro rata) |
|---|---|---|---|
| 5 days (full-time) | 1.0 | 28 days | 8 days |
| 4 days/week | 0.8 | 22.4 days | 6.4 days |
| 3 days/week | 0.6 | 16.8 days | 4.8 days |
| 2.5 days/week | 0.5 | 14 days | 4 days |
| 2 days/week | 0.4 | 11.2 days | 3.2 days |
Holiday entitlement is always rounded up — never down — when the result is not a whole number, per ACAS guidance on holiday entitlement. Bank holidays may be included in or added on top of your statutory 28 days, depending on your contract.
All calculations on this page follow ACAS pro rata pay guidelines and are consistent with the UK Employment Rights Act 1996. Tax figures use HMRC 2025/26 rates. The April 2025 National Living Wage of £12.21/hour is applied where relevant.
Related Salary Calculators
Our pro rata calculator is just one of the tools available on ProRataCalculator. You may also find these useful: term-time salary calculator, overtime calculator, holiday pay guide.
Last updated: February 2026. Verified against HMRC 2025/26 tax rates and April 2025 National Living Wage (£12.21/hour).
Frequently Asked Questions
Pro rata means "in proportion." In employment, it refers to adjusting a full-time salary proportionally based on the number of hours, days, or weeks actually worked compared to a full-time equivalent role.
Divide the full-time salary by full-time hours, then multiply by your actual hours. For example: £30,000 ÷ 37.5 hours × 25 hours = £20,000 pro rata.
Pro rata salary is usually calculated before holiday pay. Your holiday entitlement is also pro-rated — part-time workers get 5.6 weeks holiday pro rata, calculated proportionally to hours worked.
Not exactly. Pro rata is the method used to calculate part-time salary. It ensures part-time workers receive the proportional equivalent of the full-time rate, maintaining fairness under UK employment law.