A pro rata salary is a full-time salary scaled to your actual hours or time worked. The formula is simple: full-time salary × (your hours ÷ full-time hours). This page gives you the formula, worked examples for every common scenario, and tables to check your figure instantly.
The Pro Rata Salary Formula
There are three versions depending on your situation:
| Scenario | Formula |
|---|---|
| Part-time (fewer hours per week) | FTE salary × (your hours ÷ full-time hours) |
| Mid-year starter or leaver | Annual salary × (months employed ÷ 12) |
| Term-time only (e.g. school worker) | Annual salary × (weeks worked ÷ 52) |
FTE = Full-Time Equivalent. When a job advert says “£40,000 FTE”, that is the full-time salary before any pro rata reduction.
Worked Example 1: Part-Time Hours
Sarah works 25 hours per week. The full-time equivalent salary is £36,000 per year. Full-time hours at her employer are 37.5 per week.
Pro rata salary = £36,000 × (25 ÷ 37.5) = £36,000 × 0.667 = £24,000
Sarah earns £24,000 gross per year — or £2,000 per month.
After tax (2026/27):
- Income tax: £2,286 (personal allowance fully covers most earnings; 20% on £11,430)
- National Insurance: £924
- Take home: £20,790/year — £1,733/month
See our £20,000 take-home pay guide and £25,000 take-home pay guide for comparable figures.
Part-Time Salary Table: £30,000–£50,000 FTE
Use this table to find your pro rata salary. Columns show actual weekly hours; rows show the full-time equivalent salary. Full-time hours assumed: 37.5.
| FTE Salary | 15 hrs (0.4 FTE) | 18.75 hrs (0.5 FTE) | 22.5 hrs (0.6 FTE) | 25 hrs (0.67 FTE) | 30 hrs (0.8 FTE) |
|---|---|---|---|---|---|
| £25,000 | £10,000 | £12,500 | £15,000 | £16,667 | £20,000 |
| £30,000 | £12,000 | £15,000 | £18,000 | £20,000 | £24,000 |
| £35,000 | £14,000 | £17,500 | £21,000 | £23,333 | £28,000 |
| £40,000 | £16,000 | £20,000 | £24,000 | £26,667 | £32,000 |
| £45,000 | £18,000 | £22,500 | £27,000 | £30,000 | £36,000 |
| £50,000 | £20,000 | £25,000 | £30,000 | £33,333 | £40,000 |
Worked Example 2: Mid-Year Starter
James joins a new employer on 1 August 2026 with an annual salary of £42,000. The company’s holiday year runs from April to March (same as the tax year).
Salary for the partial year (August 2026 – March 2027 = 8 months):
Pro rata salary = £42,000 × (8 ÷ 12) = £28,000
James will be paid £28,000 in the period from August to March, then his full £42,000 from April 2027.
Holiday entitlement for the partial year:
28 days × (8 ÷ 12) = 18.67 days (rounded up to 19 days)
Worked Example 3: Term-Time Worker
Maria works as a school administrator, 39 weeks of the year (term-time only). Her employer’s full-time equivalent salary is £28,000 per year.
Pro rata salary = £28,000 × (39 ÷ 52) = £28,000 × 0.75 = £21,000
Maria earns £21,000 gross spread across 12 equal monthly payments of £1,750 — even though she does not work in the school holidays.
Pro Rata for Days per Week
If your contract specifies days per week rather than hours, the same formula applies — just replace hours with days, and use 5 as the full-time equivalent.
| Days per week | FTE fraction | Pro rata of £35,000 FTE |
|---|---|---|
| 1 day | 0.20 | £7,000 |
| 2 days | 0.40 | £14,000 |
| 3 days | 0.60 | £21,000 |
| 4 days | 0.80 | £28,000 |
| 5 days (full time) | 1.00 | £35,000 |
Pro Rata Holiday Entitlement
All workers — part-time, full-time, or term-time — are entitled to a minimum of 5.6 weeks’ paid holiday per year under the Working Time Regulations 1998. For full-time workers (5 days/week), this equals 28 days.
For part-time workers, the 5.6-week entitlement is the same, but 5.6 weeks of fewer hours means fewer days overall:
| Days per week | Holiday entitlement (days) | Rounded up |
|---|---|---|
| 5 days (full-time) | 28.0 | 28 days |
| 4 days | 22.4 | 23 days |
| 3 days | 16.8 | 17 days |
| 2 days | 11.2 | 12 days |
| 1 day | 5.6 | 6 days |
Key rule: Employers cannot round part-time holiday entitlement down — it must always be rounded up to the nearest half day.
For mid-year starters, entitlement is pro-rated to the remaining weeks in the leave year: 5.6 × (remaining weeks ÷ 52).
Pro Rata Salary and National Minimum Wage
An employer cannot use a pro rata calculation to pay you below the National Minimum Wage (NMW). The rate that applies is based on your age:
| Age | NMW/NLW rate (April 2026) | Minimum annual pay (37.5 hrs) |
|---|---|---|
| 21+ | £12.21/hour (National Living Wage) | £23,810 |
| 18–20 | £10.00/hour | £19,500 |
| Under 18 | £7.55/hour | £14,723 |
| Apprentice | £7.55/hour | £14,723 |
How to check: Divide your pro rata annual salary by your annual working hours. If the result is below the rate above, your employer may be in breach of NMW rules.
Example: Maria earns £21,000 for 39 working weeks × 37.5 hours = 1,462.5 hours. £21,000 ÷ 1,462.5 = £14.36/hour — well above NLW.
See our National Minimum Wage guide for current rates.
Tax and National Insurance on a Pro Rata Salary
Your pro rata gross salary is treated exactly the same as any other salary for tax purposes. The personal allowance (£12,570 in 2026/27) still applies in full — you do not receive a reduced personal allowance for working part-time.
Example — take home on £21,000 pro rata salary:
| Deduction | Annual | Monthly |
|---|---|---|
| Income tax (20% on £8,430) | £1,686 | £141 |
| National Insurance (8% on £8,430) | £674 | £56 |
| Take home | £18,640 | £1,553 |
The effective tax rate (10.6%) is lower than for a full-time worker on the same salary, because the personal allowance covers a larger proportion of total earnings. See our Take Home Pay hub for detailed after-tax figures across all salary levels.
Auto-Enrolment Pension Contributions on a Pro Rata Salary
Minimum pension contributions under auto-enrolment are:
- Employee: 5% of qualifying earnings
- Employer: 3% of qualifying earnings
Qualifying earnings are income between £6,240 and £50,270 (2026/27). These thresholds apply regardless of whether you are full-time or part-time, so the qualifying earnings band has a proportionally larger impact on part-time workers.
Example: Maria earns £21,000. Her qualifying earnings = £21,000 − £6,240 = £14,760.
- Employee contribution (5%): £738/year
- Employer contribution (3%): £443/year
- Total into pension: £1,181/year
Common Mistakes With Pro Rata Pay
| Mistake | What to do instead |
|---|---|
| Confusing FTE salary with actual salary | Check your contract — the FTE is the reference salary, not what you are paid |
| Calculating based on calendar months (not contractual months) | Use contractual months or actual weeks in period |
| Assuming holiday is also deducted for bank holidays | Bank holidays are separate — check your contract |
| Rounding holiday entitlement down | Always round up to nearest half day (legal requirement) |
| Not accounting for salary sacrifice in gross-pay calculations | Salary sacrifice reduces pensionable/gross pay, which then reduces pro rata base in some schemes |
How to Check Your Pro Rata Pay Is Correct
- Ask your employer for the full-time equivalent salary (FTE) for your role
- Confirm the full-time hours at your employer (usually 35, 37.5, or 40 hours)
- Apply the formula: FTE salary × (your hours ÷ FT hours)
- Check your payslip confirms the right gross figure
- If unsure, ACAS provides free guidance at acas.org.uk
If your employer refuses to confirm the FTE salary or your calculated pro rata pay does not match your payslip, you can raise a grievance under your employment contract or seek advice from ACAS.