Going part-time, or comparing a part-time role? Work out the pro-rata salary from the full-time equivalent — and the take-home pay that actually follows in 2026/27.
Workplace pension taken from your pay before tax (salary sacrifice). Leave at 0% to compare headline pay.
Pro rata simply means "in proportion": a £40,000 full-time salary worked 3 days out of 5 pays £40,000 × 3/5 = £24,000. Holiday entitlement scales the same way (with a legal minimum that works out at 5.6 weeks including bank holidays).
The pleasant surprise is tax: your Personal Allowance and National Insurance thresholds are not pro-rated. A part-timer still gets the full £12,570 tax-free allowance, so a bigger share of a part-time salary escapes tax — £24,000 part-time takes home proportionally more than 60% of the £40,000 take-home. Pension auto-enrolment thresholds (£10,000 trigger, contributions calculated from £6,240) also apply in full.
Comparing a switch? The pay rise calculator works just as well for a pay cut — put the pro-rata salary in as the "new salary" to see the real monthly difference.
Divide the full-time salary by the full-time days (or hours), then multiply by yours. £40,000 ÷ 5 days × 3 days = £24,000. The same fraction applies to holiday allowance.
£24,000 a year — which takes home about £1,733 a month in 2026/27, proportionally more than 60% of the full-time take-home because your £12,570 Personal Allowance is not reduced.
No — the same bands apply, and your Personal Allowance and NI thresholds stay at their full values. That is why part-time pay is taxed more lightly, pound for pound, than the same days worked at a higher salary.
Pro rata of the full-time entitlement, with a statutory minimum of 5.6 weeks a year including bank holidays. Working 3 days a week, that is 16.8 days plus your share of bank holidays, depending on your contract.