Pro rata salary calculator – work out part-time employee wages

Last checked and updated on 24 May 2022

If you’re an employer in the UK, you’ll want to make sure you’re calculating your part-time employees’ salaries correctly. Use our pro rata salary calculator to work out how much to pay them based on their hours worked.

Simply enter the full-time salary and the number of hours worked per week, and we’ll do the rest!

What does pro rata mean?

Pro rata is a Latin term which means ‘in proportion to’. When it comes to calculating salaries, pro rata refers to the way that part-time employees’ wages should be based on the number of hours they’re working. This ensures that they’re being paid fairly for the work they’re doing.

Mathematical formula to calculate pro rata pay

There’s a mathematical formula to calculate pro rata pay, which is:

((Annual full-time salary ÷ 52) ÷ Full time weekly hours) x (Number of part-time weekly hours x 52) = Annual Pro Rata salary

For example, imagine a job vacancy paying £100,000 per year full-time salary, for a 40-hour working week. If an employee was hired to work half of this role (20 hours per week) then the calculation would be:

((100,000 ÷ 52) ÷ 40) x (20 x 52) = 50,000

(The 52 in the formula is because there are 52 weeks in a year.) This is the pro rata salary that the employee should be paid for the hours they worked.

How to use our pro rata salary calculator

To use our pro rata salary calculator, simply enter the employee’s annual salary and the number of hours they’re working per week into the relevant fields. We’ll then calculate their pro rata salary for you!

How much tax and National Insurance do pro rata employees pay?

The amount of tax and National Insurance that pro rata employees pay depends on their salary and the number of hours they work per week. To calculate this, you can use our tax and National Insurance calculator.

Please note that this calculator is for illustrative purposes only and does not constitute financial advice. If you’re unsure about anything, we recommend that you seek professional payroll advice.

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Important – The information provided in our articles is intended to be for general purpose use only, and not advice for you or your business. We strive to publish accurate information, but encourage you to fact-check and seek expert guidance. We recommend that you always speak to a qualified professional to get advice about how to operate your business under your specific requirements and circumstances.