Four-Day Week FAQs
What are the different four-day models?
Three main flavours: the true four-day week (100% pay, fewer hours, same output · the model in the UK pilot trials), compressed hours (37.5 hours squeezed into four longer days, full pay), and the 80% arrangement (four days, pro-rata pay). Only the last cuts your salary · this calculator covers both money models.
How much take-home do I lose at 80% pay?
Less than 20% · usually 15-17%. The day you drop is your MOST-taxed slice of income, so gross falls 20% but net falls less. A £40,000 earner keeps about 84% of their old take-home on 80% of the hours · an hourly-rate pay rise.
What savings offset the lost pay?
One less commuting day (£10-£30/week), one less childcare day (£50-£90 for nursery children · often the game-changer), plus lunches and convenience spend. For parents of under-5s, the 80% four-day week frequently costs under £100/month net · for a full extra day every week.
What happens to pension and benefits?
At 80% pay, your and your employer's pension contributions normally shrink proportionally, and salary-linked benefits (life cover, sick pay) follow. Holiday pro-rates. The 100%-pay model leaves everything untouched · one more reason to ask for that version first.
Do I have a legal right to ask?
Yes · a day-one statutory right to request flexible working, twice a year, with a decision (and business grounds for any refusal) within two months. It is a right to ask rather than to have · but a proposal costed with this page's numbers is harder to refuse.
For informational purposes only · 2026/27 tax and NI · Assumes no pension/student loan in take-home comparison · Pension contributions and salary-linked benefits typically pro-rate at 80% pay