Four Day Week Financial Impact Calculator

Moving to a four-day week typically involves 80% pay (with productivity maintained, this is the standard offer). Salary loss is partially offset by savings: one less commute day per week, reduced childcare needs, less work-related lunches/coffee. Net financial impact often less negative than headline 20% pay cut suggests.

50,000 salary × 20% reduction = 10,000 loss. Commute savings 600 + childcare 4,000 = 4,600. Net impact: -5,400/year. 450/month for one extra day off per week. Many find this worth it for life quality, especially parents or those with long commutes. Effective hourly wage actually increases (5 days work for 4 days pay = 25% raise per hour).

4-day week pilot: 92% of companies continued post-pilot. Productivity maintained or improved at 71% of companies. Trial finding: 4-day week often net-neutral financially for employees once savings counted, while delivering 1 extra day off per week. Most financially impactful for: parents (childcare savings), long commuters (transport savings), self-care priorities.

A worked example

Try the defaults: current salary of 50,000, salary reduction of 20%, productivity change of 0%, commute savings annual of 600. The tool returns -5,400.00. You can adjust any input and the result updates as you type — no submit button, no reload. That's the real power here: seeing how sensitive the output is to one or two assumptions.

What moves the number most

The result responds to Current Salary, Salary Reduction %, Productivity Change %, Commute Savings Annual, and Childcare Savings Annual. Not every input has equal weight. Adjusting one input at a time toward extreme values shows which ones move the result most.

The formula behind this

Salary loss = current × reduction %. Total savings = commute + childcare. Net = -loss + savings. Everything the calculator does is shown in the formula box below, so you can check the math against your own spreadsheet if you want.

Using this in pay negotiations

Knowing the exact figure behind a headline rate gives you specific numbers to anchor to in conversations about pay. "The difference is £X per month after tax" lands harder than "a couple of grand a year". Concrete numbers move decisions.

What this doesn't capture

Tax bands, pension contributions, student-loan deductions, and benefits-in-kind sit outside this calculation. The figure is the headline; your actual position depends on local tax rules and personal circumstances. Pair with a dedicated take-home calculator for the full picture.