Reviewed for UK readers: September 2026.
Pro rata describes how your gross contractual salary is adjusted for a reduced working pattern. Tax is then calculated on the income you actually receive, subject to your tax code and other circumstances. Start with our pro rata pay calculator to find the gross figure; only then estimate tax and deductions.
Because Income Tax is banded, reducing a salary to part-time hours does not mean take-home pay falls by exactly the same percentage as gross pay.
Quick answer
- Calculate gross pro rata salary first.
- PAYE tax is based on taxable pay and your tax code.
- A lower gross salary can move income between tax bands.
- Scottish taxpayers use different employment-income bands.
The 2026/27 Personal Allowance
For 2026/27 the standard Personal Allowance is £12,570, subject to eligibility and reduction for higher incomes. In England, Wales and Northern Ireland, taxable employment income above the allowance is generally charged at the basic, higher and additional rates. Scotland has separate bands and rates for employment income.
Example: £40,000 full time to 0.6 FTE
A £40,000 FTE role at 0.6 FTE gives £24,000 gross annual salary. That does not mean tax is 60% of the tax on £40,000. More of the reduced salary may sit within the Personal Allowance and basic-rate band, so the tax reduction can be proportionally larger than the salary reduction.
National Insurance and pension
Take-home pay also depends on employee National Insurance, workplace pension contributions, student or postgraduate loan deductions, salary sacrifice and other payroll items. A salary-only pro rata calculator should not present those deductions as part of the contractual salary.
Tax codes matter
Two employees on the same gross salary can have different PAYE deductions because their tax codes differ. Benefits, previous underpayments, multiple jobs and other circumstances can affect the code used by payroll.
When to use HMRC tools
For an official view of your PAYE position, check HMRC’s current tax information and your Personal Tax Account. Use online salary estimates for planning, not as a substitute for a payslip or personalised tax advice.
What a pro rata tax estimate cannot know
A general calculator cannot see your live tax code, earlier pay in the tax year, benefits, second jobs, pension method, student loans or HMRC adjustments. Use a pro rata calculation to establish gross salary, then treat any take-home figure as an estimate until it is confirmed by payroll or HMRC.
If your circumstances are unusual, use current HMRC information rather than relying on an old tax table. Rates and thresholds can change between tax years.
Use the calculator
For a quick gross salary estimate, use the Pro Rata Calculator UK. Enter the full-time salary and your hours, days or FTE, then compare the result with your contract or payroll figure.
Frequently asked questions
Is pro rata salary before or after tax?
Job adverts and employment contracts normally quote pro rata salary as gross pay before tax and other deductions.
Does going part time reduce my tax rate?
It may reduce the amount of income falling into higher bands, but the result depends on total taxable income and your tax code.
Is the Personal Allowance pro rated because I work part time?
The standard Personal Allowance is an annual tax allowance and is not simply multiplied by your FTE percentage.
Does Scotland use the same tax bands?
No. Scottish taxpayers have separate rates and bands for employment income.
Authoritative sources