Pro Rata Salary Calculator UK 2026/27

Pro rata is Latin for "in proportion". When an employer offers a part-time role, they scale the full-time salary to match the hours or days you actually work. This ensures part-time employees are paid fairly compared to their full-time colleagues.

The pro rata salary formula is straightforward: divide the full-time salary by the full-time hours (or days) per week, then multiply by your actual hours (or days). For example, if a full-time role pays £30,000 for 37.5 hours a week and you work 25 hours, your pro rata salary is (£30,000 ÷ 37.5) × 25 = £20,000.

Employers use pro rata calculations to determine salary, holiday entitlement, pension contributions, and other benefits for part-time staff. UK employment law requires that part-time workers receive treatment no less favourable than full-time workers on a pro rata basis.

Let's say you're offered a part-time role where the full-time equivalent salary is £30,000 for 37.5 hours per week. You'll be working 25 hours per week. Here's how the pro rata salary calculator works it out:

After income tax, National Insurance (8%), a 5% workplace pension contribution and no student loan, your take-home pay on £20,000 would be approximately £17,200 per year (£1,433 per month). Use our pro rata salary calculator above to see the exact breakdown for your situation. Tax and NI figures are for 2026/27 (Rest of UK, 1257L tax code). Pension is deducted before tax, reducing your taxable income.

You'd also be entitled to 18.7 days of holiday per year (25 ÷ 37.5 × 28 statutory days), compared to 28 days for a full-time employee.

Many employers define full-time as a set number of days per week — typically 5 days. If you work fewer days, your salary is scaled proportionally using the same pro rata formula.

Example: Full-time is 5 days per week. You work 3 days. The full-time salary is £30,000.

Below is a quick reference for a £30,000 full-time salary (5-day week):

Some roles — particularly in education, childcare and seasonal industries — are paid only for the weeks actually worked. Teachers on term-time only contracts, supply staff, and seasonal workers typically fall into this category.

To convert a term-time salary to a full-year equivalent, you need to account for the proportion of the year you work:

Example: A teacher works 39 school weeks per year at 0.6 FTE (3 days per week). The full-time equivalent salary is £30,000.

Important: Your holiday entitlement is still 5.6 weeks per year under UK law, but for term-time workers it is calculated differently. If you work 39 weeks, your employer may include bank holidays within those weeks or provide additional paid leave on top — check your contract.

When comparing part-time job offers, it helps to convert each salary to a full-time equivalent (FTE) so you can compare like-for-like. This tells you what the role would pay if it were full-time.

Example: You're offered £20,000 for 25 hours per week, and the full-time role is 37.5 hours.

This means the role pays exactly the same rate as a £30,000 full-time position — you just work fewer hours. If the FTE salary is lower than competing full-time roles, you may be being underpaid relative to the market.

You can also use FTE to compare roles with different hours. A job paying £22,000 for 30 hours/week has an FTE of £29,333, while £24,000 for 35 hours/week has an FTE of £27,429 — the first offer is actually better value.