Is working a fifth day worth it?
Going down to four days costs you less than a fifth of your take-home pay. See what your fifth day really earns.
Your answer
Enter your full-time salary to see what your fifth day earns.
About this calculator
For anyone thinking about a four-day week, or asking for one. It assumes four days are paid at four-fifths of your full-time salary.
What happens to your answers
We don’t keep them. Your answers go to our server to do the sums and aren’t stored or logged. If you copy a link to your answers, they’re in the link itself, so only share it with people you trust.
How it’s worked out
We work out your take-home pay on your full salary and on 80% of it. Your fifth day's pay is the top slice of your income, taxed at your highest rate, so you keep less of it than of the other four days.
Worked example
Your fifth day earns you £102.12 a week after tax, £5,310 a year.
2026/27 tax year · England · 5% pension taken before tax · Plan 2 student loan · four days paid at 80%
| Five days: you take home | £32,714 |
|---|---|
| Four days: you take home | − £27,404 |
| Your fifth day adds, a year | £5,310 |
| That's, for each week | £102.12 |
| It also adds to your pension, a year | £450 |
Worked out using HMRC's published rates for the 2026/27 tax year (6 April 2026 to 5 April 2027), on a yearly basis.
Questions people ask
What about my holiday and pension?
Holiday is usually reduced in proportion on four days. Your pension contributions fall with your pay; we show how much less goes in.
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