Pro Rata Salary Calculator

Whether you’re checking a part-time job offer, working out what a reduced-hours contract actually pays, or just trying to see if your payslip adds up, this pro rata salary calculator gives you the answer straight away. Enter the full-time salary and your hours, and you’ll get your pro rata pay broken down by year, month, week and hour. No sign-up, no spreadsheets, no guesswork.

Job adverts usually quote the “full-time equivalent” salary — often shortened to FTE. That’s the figure for someone doing the full hours, usually 37.5 or 40 hours a week depending on the employer. If you’re working less than that, your pay is scaled down in proportion. That’s all “pro rata” means: in proportion.

In short: a pro rata salary is the full-time salary scaled down to your hours — multiply the full-time salary by (your hours ÷ full-time hours). For example, £30,000 a year at 22.5 hours of a 37.5-hour week is £18,000. Term-time contracts need a second step: multiply again by (your weeks ÷ 52).

How this pro rata salary calculator works

The formula is straightforward:

Pro rata salary = full-time salary × (your hours ÷ full-time hours)

Working in days rather than hours? Use the same formula with days instead. A £30,000 role worked over 3 days instead of a full 5-day week comes to £30,000 × (3 ÷ 5) = £18,000. Both methods land on the same figure as long as your daily hours stay consistent.

Term-time and part-year contracts need a second step, because you’re working fewer weeks a year as well as (often) fewer hours a week:

Term-time salary = full-time salary × (your hours ÷ full-time hours) × (your weeks ÷ 52)

This matters a lot in schools. A teaching assistant on term-time hours might work full 37.5-hour weeks but only 39 weeks of the year — the weekly hours are full-time, but the salary still gets scaled down for the shorter year.

2026/27 tax bands (for working out your take-home)

The pro rata salary calculator shows gross pay. What’s left after tax depends on the current thresholds:

Detail	2026/27 figure
Personal allowance	£12,570
Basic rate: 20%	£12,571 – £50,270
Higher rate: 40%	£50,271 – £125,140
Additional rate: 45%	Above £125,140
Employee National Insurance	8% on £12,570 – £50,270, then 2% above

So a pro rata salary of £18,000 means £5,430 of it sits above the personal allowance and gets taxed at 20% — £1,086 in Income Tax for the year, plus employee NI at 8% on the same £5,430, which is £434.40. Rough take-home: around £16,479.60 before pension deductions. That’s the sort of sum worth doing before you accept an offer.

Worked examples

Example 1: reduced hours

Full-time salary £30,000, based on a 37.5-hour week. You’re taken on for 22.5 hours a week.

£30,000 × (22.5 ÷ 37.5) = £30,000 × 0.6 = £18,000 a year.

That’s £1,500 a month gross (£18,000 ÷ 12).

Example 2: term-time contract

A teaching assistant on a £26,000 FTE salary, working full 37.5-hour weeks but only 39 weeks of the year.

The hours ratio is 37.5 ÷ 37.5 = 1, so it drops out. The weeks ratio does the work:

£26,000 × (39 ÷ 52) = £26,000 × 0.75 = £19,500 a year.

Term-time pay is usually spread evenly across 12 months, so that’s £1,625 a month — including through the summer holidays when you’re not working. If your payslip shows a flat monthly figure rather than dropping to zero in August, that’s why.

Example 3: hourly comparison

Full-time salary £32,000, 37.5-hour weeks. What’s the hourly rate, for comparing against hourly-paid offers?

£32,000 ÷ 52 ÷ 37.5 = £615.38 per week ÷ 37.5 = £16.41 per hour.

This is the figure to use when someone offers you £15 an hour and you want to know whether it beats the salaried role. (It doesn’t, in this case.)

Example 4: comparing two offers

Two part-time offers: one at £28,000 FTE for 3 days a week, one at £32,000 FTE for 4 days a week (both on a 5-day full-time pattern).

Offer A: £28,000 × (3 ÷ 5) = £16,800 a year.
Offer B: £32,000 × (4 ÷ 5) = £25,600 a year.

The headline FTE figures are £4,000 apart, but the actual pay difference is £8,800 — nearly double. Run each offer through the pro rata salary calculator separately and compare the annual and hourly figures side by side before you decide.

What your result means, and what to do next

The figure you get is your gross annual salary before Income Tax, National Insurance and pension deductions. Use the 2026/27 bands above — or estimate what NI and tax come off your pro rata salary with our National Insurance calculator.

Then check it against reality. Find the full-time equivalent salary for your role (it should be in your contract or the original job advert), divide your actual hours by the full-time hours, and multiply. If the number on your payslip doesn’t match, don’t assume the payroll department got it wrong straight away — check whether you’re on a term-time contract with pay spread over 12 months, or whether your “full-time” baseline is 40 hours rather than 37.5. Those two things explain most mismatches.

One point of law worth knowing: part-time workers have the right to the same hourly rate as a comparable full-time employee doing the same job. If your pro rata calculation reveals you’re being paid less per hour simply because you work part-time, that’s worth raising with your employer. On a pro rata contract and planning a family? See how maternity pay works on a pro rata contract. For time off ill, check statutory sick pay for part-time workers.

Your holiday, including bank holidays

Part-time and pro rata staff get the same proportion of holiday as full-time colleagues. The statutory minimum is 5.6 weeks a year, so someone working 3 days a week is entitled to 5.6 × 3 = 16.8 days’ leave. Your employer can round, but the principle is fixed: pro rata holiday, not fewer weeks off.

Bank holidays are the bit that trips people up. You’re entitled to your pro rata share of the 8 UK bank holidays — not just whichever ones happen to land on your working days. Say you work Tuesday to Thursday and every bank holiday falls on a Monday. Your employer still owes you (3 ÷ 5) × 8 = 4.8 days off in lieu. They can’t just say you get none because none fall on your working days. If your contract says “plus bank holidays” without specifying, ask how they’ve calculated your share.

Common mistakes with a pro rata salary calculator

Mixing hours and days in the same calculation. Pick one unit and stick with it. If the full-time pattern is 37.5 hours over 5 days and you work 22.5 hours over 3 days, both ratios give 0.6 — but only if you’re consistent.

Forgetting the second step on term-time contracts. Hours and weeks both scale the salary. A teaching assistant working full-time hours during term time is still part-year, and the weeks ratio is usually the bigger cut.

Assuming bank holidays are free days off. They’re part of your pro rata entitlement, not a bonus on top. If you work part-time, your share of the 8 bank holidays needs calculating separately.

Comparing FTE figures instead of actual pay. A higher FTE salary on fewer days can easily pay less in real terms, as the worked example above shows. Always compare the pro rata figures — and the hourly rates.

Treating the gross figure as take-home. The calculator shows pay before tax, NI and pension. On £18,000 a year, roughly £1,520 disappears to Income Tax and employee NI. Check the take-home before budgeting.

Frequently asked questions