Pro Rata Meaning: What Is Pro Rata Pay & How to Calculate It

What is pro rata pay?

Pro rata pay is salary calculated as a proportion of a full-time equivalent (FTE) figure. It applies whenever you work fewer hours than the standard full-time week — including part-time roles, term-time contracts, job-shares, and mid-month joiners paid for only part of the payroll period.

Employers advertise salaries “pro rata” so candidates can compare against the FTE rate. A listing that says “£40,000 pro rata, 3 days per week” pays £24,000 actual salary but signals the role pays £40,000 on a full-time basis.

Pro rata pay is different from an hourly wage: it's an annual salary that has been scaled down, with tax, National Insurance, and pension deductions all applied to the reduced figure. See our hourly wage calculator if you'd prefer to work in hourly terms.

How to Calculate Pro-Rata Salary

The pro-rata salary formula is straightforward. You divide the number of hours you work by the full-time hours, then multiply by the full-time equivalent (FTE) salary.

Here are some common examples based on a standard 37.5-hour full-time week (5 days of 7.5 hours):

Use our pro-rata salary calculator to work out your exact figure based on any combination of hours and salary.

How to calculate a part-month salary (UK)

If you start or leave a job partway through the month, most UK employers calculate a pro rata amount based on working days. The standard formula is:

Worked example: You start on the 16th of a month that has 22 working days in total, on a £36,000 annual salary. You'll work 15 of those days.

• • Daily rate: £36,000 ÷ 260 = £138.46
• • Part-month pay: £138.46 × 15 = £2,076.92 (gross)

Some employers use calendar days (365 or 366) instead of working days (260), which produces a slightly different figure. Others use the employee's contracted hours for the month. Check your contract or payslip for the exact method — all three are legal.

For a quick take-home estimate on a one-off part-month payment, enter the gross figure into our take-home pay calculator, or use our pro-rata calculator for ongoing part-time arrangements.

Pro-Rata Holiday Entitlement

Full-time workers in the UK are entitled to a minimum of 28 days of paid holiday per year (including bank holidays). Part-time workers receive a proportional share based on the days or hours they work.

For detailed guidance on calculating your specific entitlement, see the official GOV.UK holiday entitlement page.

Tax Advantages of Part-Time Work

One of the key financial benefits of part-time work is that you still receive the full £12,570 personal allowance. This means a larger proportion of your income is tax-free compared to your full-time equivalent salary.

Compare these to the full-time rates: someone earning £60,000 full-time would enter the 40% higher rate band, but working 3 days keeps the pro-rata salary of £36,000 entirely within the basic rate band. Read more about how this affects your pay in our UK tax changes 2026/27 guide.

Pro-Rata Pension Contributions

When you work part-time, your pension contributions are calculated based on your actual pro-rata salary, not the full-time equivalent. Under auto-enrolment, you contribute a minimum of 5% of qualifying earnings and your employer contributes at least 3%.

The good news is that tax relief still applies at your marginal rate. If you are a basic rate taxpayer, you get 20% tax relief on every pound you contribute to your pension. This makes pension contributions particularly efficient for part-time workers who stay within the basic rate band.

For a deeper look at how to make the most of your pension tax relief, read our guide on pension contributions and tax relief.

Your Rights as a Part-Time Worker

The Part-Time Workers (Prevention of Less Favourable Treatment) Regulations 2000 protect part-time employees from being treated less favourably than comparable full-time workers. This covers several important areas:

• ✓Equal hourly rate as full-time colleagues in comparable roles
• ✓Same access to training and career development opportunities
• ✓Equal consideration for promotion and transfer opportunities
• ✓Fair redundancy selection criteria and payments

For full details on your legal rights, see the official GOV.UK part-time worker rights page.

Term-Time Only Contracts

Term-time only contracts work differently from standard part-time arrangements. Instead of reducing hours per week, you work full weeks but only during school terms. The calculation accounts for the number of weeks worked rather than just hours per week.

For example, a teaching assistant working 39 weeks per year (out of 52) at a full-time salary of £25,000 would receive a pro-rata salary of approximately £18,750 (39/52 × £25,000). This is usually spread across 12 monthly payments for consistency.

If you are on a term-time contract and want to understand your effective hourly rate, our hourly wage calculator can help you work out what you are earning per hour.