Four day week calculator
A four-day week costs you a fifth of your salary and about a sixth of your take-home. Whether that is a good trade is a real question, and it deserves the actual numbers rather than a shrug.
That is £35,920 a year after income tax, National Insurance and anything else coming off your pay.
- Income tax
- £6,486
- National Insurance
- £2,594
- Effective rate
- 20.2%
- Marginal rate
- 28.0%
| Year | Month | Week | Hour | |
|---|---|---|---|---|
| Gross pay | £45,000.00 | £3,750.00 | £865.38 | £23.08 |
| Income tax | £-6,486.00 | £-540.50 | £-124.73 | £-3.33 |
| National Insurance | £-2,593.92 | £-216.16 | £-49.88 | £-1.33 |
| Take-home pay | £35,920.08 | £2,993.34 | £690.77 | £18.42 |
What one day a week costs
| Full-time salary | On four days | Net loss a year | A month | % of net given up |
|---|---|---|---|---|
| £28,000 | £22,400 | £4,032 | £336.00 | 17.0% |
| £35,000 | £28,000 | £5,040 | £420.00 | 17.5% |
| £45,000 | £36,000 | £6,480 | £540.00 | 18.0% |
| £55,000 | £44,000 | £7,258 | £604.83 | 17.1% |
| £70,000 | £56,000 | £8,120 | £676.67 | 15.9% |
| £95,000 | £76,000 | £11,020 | £918.33 | 16.8% |
| £115,000 | £92,000 | £10,340 | £861.67 | 13.9% |
Where the trade is best
At £115,000 dropping to four days costs about 15% of your take-home, because the fifth day was being taxed inside the Personal Allowance taper at 62p in the pound. At £28,000 it costs about 19%, because almost none of your income was above the basic rate.
That is the counter-intuitive part: the four-day week is cheapest, in net terms, for exactly the people who could most afford five. If you are inside the taper and thinking about it, the arithmetic is closer than the salary makes it look.
Questions people actually ask
How much less will I take home on four days?
Between about 15% and 19% of your take-home depending on where you sit, against a flat 20% cut in gross. The gap is entirely down to the Personal Allowance staying whole and the top slice of your income disappearing first.
Does a four-day week affect my pension?
Yes, proportionally. Contributions fall with pay, and in a tiered scheme you may move down a tier, which reduces the percentage as well as the base. In a defined benefit scheme it also reduces the service accrued.
Related
Figures on this page are for the 2026/27 tax year (6 April 2026 to 5 April 2027) and were last checked on 29 August 2026. Every rate we use is listed on the sources page.