Pro Rata Salary Calculator UK

If you're moving to part-time hours, starting a job partway through the year, or being paid for a reduced work pattern, you need to know your pro rata salary, not your full-time equivalent. Our pro rata salary calculator converts a full-time annual salary into the amount you'll actually be paid based on the hours or days you work, giving you an accurate figure for budgeting, contract negotiations, or comparing job offers.

Whether you're a job seeker sizing up an advertised salary, an employee reducing your hours, or an employer working out fair pay for a part-time role, this tool gives you a precise breakdown in seconds, no spreadsheet required.

What is a pro rata salary?

A pro rata salary is a proportion of a full-time salary, calculated based on the hours or days someone actually works compared to a standard full-time schedule. "Pro rata" is Latin for "in proportion," and in UK employment it's most commonly used for part-time roles, job shares, term-time contracts, and any position where someone works less than the standard 37.5 or 40 hours a week.

You'll see pro rata salaries most often in job adverts, where an employer lists the full-time equivalent (FTE) salary and notes that the actual pay will be "pro rata" to the hours advertised. For example, if a full-time role pays £30,000 a year for 40 hours a week, someone working 20 hours a week on the same role would earn £15,000 pro rata, exactly half. It's a fair and standard way to scale pay to reflect time actually worked, and it applies just as much to holiday entitlement, sick pay, and pension contributions as it does to salary.

How to calculate pro rata salary

The standard formula is:

Pro rata salary = (Full-time salary ÷ Full-time hours) × Actual hours worked

Or, if you're working a reduced number of days rather than hours:

Pro rata salary = (Full-time salary ÷ Full-time days) × Actual days worked

Worked examples

Worked example by days: A full-time salary of £35,000 is based on a 5-day week. If you work 3 days a week, £35,000 ÷ 5 = £7,000 per day, then £7,000 × 3 = £21,000 pro rata salary.

Worked example by hours: A full-time salary of £28,000 is based on a 37.5-hour week. If you work 22.5 hours a week, 22.5 ÷ 37.5 = 0.6, then £28,000 × 0.6 = £16,800 pro rata salary.

Worked example for a part-year contract: A term-time-only support worker role pays £24,000 FTE for a full 52-week year, but the post only runs for 39 weeks. £24,000 ÷ 52 = £461.54 per week, then £461.54 × 39 = £18,000 pro rata salary.

This last scenario is common in education and public sector roles, where a job might be full-time hours but part-year in duration. The pro rata adjustment applies to weeks worked rather than hours.

How to use this calculator

• Enter the full-time annual salary for the role, using the FTE figure from the job advert or contract.
• Enter the standard full-time hours per week, usually 37.5 or 40 hours.
• Enter the actual hours you work each week.
• Enter the number of months worked in the year if the role is part-year or started partway through the year.

The calculator shows your pro rata annual salary, plus a monthly and weekly breakdown, so you can see exactly what to expect in each pay cycle.

The result is a gross figure before Income Tax and National Insurance are deducted. To see what actually lands in your bank account, run the pro rata figure through our Income Tax Calculator for a full take-home pay breakdown.

Why pro rata calculations matter

Getting your pro rata salary right matters for a few practical reasons:

• Comparing job offers. A part-time role advertised at "£40,000 pro rata" pays far less than £40,000 if you're only working three days a week. Job adverts don't always make this obvious, so working out the real annual figure prevents disappointment on your first payslip.
• Term-time and school-year contracts. Many education and support roles are paid pro rata across term time only, not 52 weeks a year, meaning the monthly pay you receive is usually smoothed across 12 months even though you're not working every week.
• Budgeting for reduced hours. If you're negotiating a move from full-time to part-time work, knowing your real take-home helps you plan your finances before agreeing to the change with your employer.
• Checking payslips. Pro rata calculations help you verify your employer has applied the right proportion to your pay, especially if your hours have recently changed or you've started or left a role partway through a month.
• Employer fairness and compliance. Employers use pro rata calculations to ensure part-time staff are paid fairly relative to full-time colleagues doing the same role, which is a legal requirement under the Part-time Workers Regulations.

Pro rata holiday and other entitlements

Salary isn't the only thing calculated pro rata. Statutory holiday entitlement, sick pay, and pension contributions are usually adjusted the same way. Full-time UK workers are entitled to 5.6 weeks' paid holiday a year, which is 28 days for a standard 5-day week. Part-time workers receive the same proportion based on the days or hours they work.

If you also need to check how much annual leave you're entitled to on a part-time or irregular contract, our Holiday Entitlement Calculator works this out automatically.

If your working pattern changes partway through the tax year, for example starting a new job in October rather than April, your total tax liability for the year is also affected. Our Part-Year Employment Calculator is built specifically for this scenario and can be used alongside your pro rata salary figure.

Pro rata salary vs hourly rate

Some people find it easier to think in terms of an hourly rate rather than a pro rata annual salary, particularly for casual, freelance, or highly variable hours. If you'd rather convert a salary into an hourly figure, or vice versa, use our Hourly Rate Calculator, which does the same underlying maths from the opposite direction.

Similarly, if you're negotiating a new contract and know the take-home pay you need rather than the gross salary, our Net to Gross Salary Calculator can help you work backwards to the right pro rata figure to ask for.