2026/27 Salary Two jobs Compare pay Pro-rata

Pro-Rata Salary Calculator

Enter your full-time contract salary and the proportion you actually work. We show your pro-rata pay, take-home, tax and National Insurance for 2026/27, and compare it side-by-side against the full-time figure.

Your details — 2026/27
£
Annual salary for the full-time equivalent role.
e.g. 50 for half-time.
Advanced options
Your pro-rata take-home
—
Eff. rate — per year
Pro-rata gross: —
Full-time vs Pro-rata
Full-time
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Full-time contract salary
Income tax—
National Insurance—
Take-home—
Pro-rata
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— of full-time
Income tax—
National Insurance—
Take-home—
What you give up by working part-time

How pro-rata pay is calculated

Pro-rata means "in proportion". Your actual salary is your full-time contract salary multiplied by the fraction of full-time you work. If a full-time role pays £40,000 and you work 3 out of 5 days, your pro-rata salary is:

£40,000 × (3 ÷ 5) = £24,000

Income tax, National Insurance and (where applicable) student loan repayments are then calculated on that pro-rata figure, not the full-time one. Because the personal allowance and NI thresholds are fixed amounts, working part-time usually means a lower effective tax rate as well as lower pay.

What counts as full-time?

There is no single legal definition of full-time in the UK — it is whatever your employer defines in the contract. Use your employer's full-time hours or days to get an accurate proportion.

Frequently asked questions

How is a pro-rata salary calculated?

Multiply the full-time salary by your contracted hours divided by full-time hours (or by your full-time-equivalent fraction). For example, 22.5 of 37.5 hours is 60% of the full salary.

Are tax and National Insurance pro-rated too?

No. Income Tax and NI thresholds are annual amounts that are not reduced for part-time work. Tax is charged on your actual pro-rata pay, so your effective rate can differ from a full-time colleague.

How does pro-rata affect my pension?

Workplace pension contributions are usually based on your actual pro-rata pensionable pay, so both your contribution and your employer contribution are lower in cash terms.

Is holiday pay pro-rated?

Statutory holiday is 5.6 weeks a year for full-time staff, pro-rated for part-time hours. Bank holidays may be included depending on your contract.