The idea of a 4-day work week is gaining momentum. But the financial fear holds many people back: "I cannot afford a 20% paycut." The reality is more nuanced. Because of how the UK tax system works, dropping to 80% of your salary does not mean 80% of your take-home pay. The loss is significantly smaller than you think.
Why the impact is less than 20%
The income you "lose" is always from your highest marginal tax band. If you earn £50,000 and drop to £40,000, the £10,000 you give up was being taxed at 40% (income tax) + 2% (NI) = 42%. You were only keeping 58% of it anyway. Your actual take-home loss is closer to £5,800 — not £10,000.
Worked examples
These compare full-time vs. 4-day (80% salary) take-home for 2026/27, using standard assumptions (no pension, no student loan):
| Full-time salary | 4-day salary (80%) | Monthly take-home loss | Real % reduction |
|---|---|---|---|
| £30,000 | £24,000 | ~£350 | ~17% |
| £50,000 | £40,000 | ~£480 | ~15% |
| £75,000 | £60,000 | ~£650 | ~14% |
| £100,000 | £80,000 | ~£750 | ~13% |
Approximate figures — use the calculator for exact numbers with your specific situation.
Additional savings from reduced hours
A 4-day week often brings cost savings that offset the pay reduction further:
- One fewer day of commuting (fuel, fares, parking)
- Reduced childcare costs
- Fewer lunches, coffees, and work-related expenses
- Less need for convenience spending (takeaways due to tiredness)
Impact on pension and other benefits
Check with your employer how a reduced salary affects pension contributions (percentage-based contributions will be lower in absolute terms), life insurance cover, and any income-linked benefits.
Model your exact scenario
Enter both your current salary and your 80% salary into the income tax calculator and compare the two monthly take-home figures. The difference is your true monthly cost of a 4-day week.