The four-day work week has a headline statistic that gets repeated everywhere: 92% of companies in the world’s biggest trial kept it. That number is real. It is also about the average across 61 companies of wildly different sizes — some with hundreds of employees and dedicated HR teams to redesign workflows around the missing day, and some with eight people where one person’s absence on a Friday is the whole company running short-handed.
For a founder actually deciding whether to try this, the average obscures the only question that matters: what happened inside businesses that look like yours.
The trial everyone cites
From June to December 2022, 61 UK companies and roughly 2,900 employees took part in the largest four-day week pilot run anywhere, coordinated by the nonprofit 4 Day Week Global together with the UK think tank Autonomy and researchers from the University of Cambridge and Boston College. The model was “100-80-100”: 100% of pay, for 80% of previous hours, on the condition that the company maintained 100% of its output.
The results, published in February 2023 and widely reported by outlets including the World Economic Forum and CNBC, were emphatic on the wellbeing side: 56 of the 61 companies (92%) continued with the four-day week once the formal trial ended, and 18 confirmed the change as permanent immediately. Employees reported real gains — 39% said they were less stressed, and 71% reported reduced burnout, with lower anxiety and fatigue and improvements in both physical and mental health. Staff turnover fell sharply during the trial period, and company revenue held broadly steady rather than declining, which was the outcome most participating employers said they were actually worried about going in.
None of that answers what a two-person or ten-person company should expect, because most of the pilot’s participants weren’t that small. The pilot’s own published case studies are where that answer actually lives.
What it looked like inside the smallest companies
Rivelin Robotics, an eight-person robotics startup in Sheffield, was one of the smallest companies in the trial. The team took Fridays off and extended its Monday-to-Thursday hours to cover the gap. CTO David Alatorre framed the decision as being about people first, not a productivity bet: “We wanted to instill a culture in the company that puts well-being first, ensuring that everyone is rested and has a good work-life balance.” Coverage of Rivelin’s experience during the pilot also noted the switch came with genuine speed bumps as a team that small worked out how to redistribute the work of a missing day — the kind of friction that a 500-person company can absorb in a way an 8-person one cannot.
That’s the honest picture the 92% headline leaves out: the pilot’s aggregate result is real, but it’s an average of companies that had very different amounts of slack to work with.
Two founders who didn’t wait for a trial
Two small businesses outside the official UK pilot show what it looks like when it’s a founder’s own decision, sustained for years rather than a single trial period.
Louise Verity founded Bookishly, an online shop selling gifts for book lovers, in 2009, and had her own doubts about a shorter week. The pandemic changed how she thought about it, and she joined the UK pilot with her now-11-person team in 2022. Rather than stopping at the trial’s original end date, Bookishly extended it by an additional six months to see how a four-day week held up through the Christmas peak — the hardest possible season to test it on a small retail operation. It held up. Wednesdays off are now permanent and written into every new hire’s contract.
In Edmonton, Shani Gwin founded the public relations agency pipikwan pêhtâkwan and moved her roughly 25-person team to Fridays off in August 2021 — a full year before the UK pilot even started, and with no formal research program backing the decision. As CBC News reported, the switch has stuck for years since, on an agency’s own read of what it needed to retain and support a small team.
Neither of these are trial participants with academic researchers measuring their output. They’re two specific, named founders who made the call and kept it going well past the point where reverting would have been the easy option — which is arguably a stronger signal than a six-month pilot for whether the model actually survives contact with a real, ongoing small business.
What this actually means if you’re deciding
- The 92% figure is real, but it describes an average, not a guarantee. It includes companies far larger than most independent businesses, with more slack to redesign around a missing day.
- Smallest doesn’t mean impossible — it means more friction up front. Rivelin Robotics’ experience suggests an 8-person team should expect real adjustment costs, not a clean switch, especially if the motivation is wellbeing rather than a specific efficiency gain already identified.
- The businesses that made it stick redesigned the work, not just the calendar. Bookishly extended its own trial through the hardest season on purpose, specifically to stress-test the decision before calling it permanent.
- You don’t need a formal pilot to try this. Shani Gwin moved her agency to a four-day week a year before the UK trial existed. The research is useful for knowing what’s plausible; it isn’t a prerequisite for testing it in your own company.
- Revenue held up in the aggregate trial data, but “held up” is the honest claim — not “grew.” Treat a four-day week as a wellbeing and retention bet first, and let any output gain be the upside rather than the premise you’re relying on.
Related reading
- Founder Burnout: What the Research Actually Shows — the research on what actually drives burnout risk for founders, and why it isn’t simply hours worked.
- Do Founders Need Less Sleep? What the Research Shows — another case where founder folklore about working harder doesn’t hold up against the data.
- How Much Should Founders Pay Themselves? — a second evergreen founder question where the honest answer is a range, not a single confident number.
The UK 2022 four-day week pilot figures — 61 companies, roughly 2,900 employees, June–December 2022, the 100-80-100 model, 56 of 61 companies (92%) continuing and 18 confirming a permanent change, 39% of employees reporting less stress and 71% reporting reduced burnout — are per the pilot organizers’ published results (4 Day Week Global and the Autonomy Institute) and reporting by the World Economic Forum and CNBC. The Rivelin Robotics account and the David Alatorre quote are per Now Then Sheffield’s coverage of the company’s participation in the pilot. The Bookishly account, including Louise Verity’s decision to extend the company’s trial through the Christmas season before making it permanent, is per Shopify’s own published case study. The pipikwan pêhtâkwan account, including Shani Gwin’s August 2021 switch to a four-day week, is per CBC News.
