Part-Time Hours Calculator
See exactly what dropping to fewer hours, a 4-day week or reduced hours, really does to your take-home pay. Because tax is progressive, your net pay usually falls by LESS than your hours do.
Estimate only. 2026/27 estimate, verify with gov.uk/HMRC; not tax or employment advice. Flexible working requests are subject to your employer's statutory process.
Enter your salary and hours
Your before-and-after take-home pay, and the real cost of the hours you're giving up, appear here.
Why cutting hours costs less than it looks
Income Tax and National Insurance are progressive, the more you earn, the higher the rate on your last pound of income. Your Personal Allowance (the first slice of income that's tax-free) doesn't shrink with your salary, so a pay cut removes income from the TOP of your earnings, where it was being taxed hardest. The practical result: dropping to 80% of your hours very often costs you less than 20% of your take-home pay. This calculator runs your current and reduced salary through the same take-home pay engine used across the site, so the comparison reflects real 2026/27 Income Tax and National Insurance rates, not a rough rule of thumb.