The 4-Day Workweek Works Better Than Anyone Expected
The largest 4-day workweek trial ever conducted revealed something researchers didn't expect: productivity went UP while hours went DOWN. Here's what changed.
The 4-Day Workweek Works Better Than Anyone Expected
In 2022, 61 British companies embarked on the world's largest four-day workweek pilot. For six months, 2,900 employees worked 80% of their hours for 100% of their pay—with one condition: productivity had to stay the same. The results? Revenue increased by 1.4% on average across participating companies. Sick days dropped by 65%. Staff turnover fell by 57%.
But here's the number that stunned researchers: 92% of participating companies chose to continue the four-day schedule after the trial ended. Only three companies decided to stop. Of those continuing, 18% made the change permanent immediately. This wasn't what economists predicted.
The data raises a question that challenges a century of assumptions about work: What if working fewer hours actually makes people more productive, not less?
The Hidden Math of the 80/100 Model
The trial, coordinated by the non-profit 4 Day Week Global and researchers at Cambridge and Boston College, wasn't about compressed hours. Employees didn't work 10-hour days to squeeze 40 hours into four days. They genuinely worked fewer hours—typically 32 instead of 40—while producing the same output.
[!INSIGHT] Companies didn't just maintain productivity—they improved it. Revenue per employee increased by 8.82% during the trial period when normalized for industry.
How did employees accomplish the same work in less time? The answer lies in what the researchers call "productivity hidden in plain sight."
A 2019 study by VoucherCloud found that the average British office worker is only productive for 2 hours and 53 minutes per day. The rest is consumed by meetings, email, Slack messages, water cooler conversations, and—most significantly—"looking busy." When given one fewer day to complete tasks, employees naturally compressed their actual work into focused bursts.
The Meeting Massacre
One participating company, a digital marketing agency in London, reduced its meeting time by 40% overnight. They implemented three simple rules: no meetings longer than 30 minutes, no meetings without agendas, and Tuesdays and Thursdays as meeting-free days.
“*"We discovered that about 60% of our meetings were ceremonial”
The phenomenon wasn't isolated. Across the trial, average meeting times dropped by 35%, while project completion rates held steady or improved.
The Wellbeing Dividend
Researchers measured more than productivity. Using validated psychological assessment tools, they tracked employee wellbeing across multiple dimensions.
| Metric | Change |
|---|---|
| Work-life balance satisfaction | +60% |
| Stress levels | -40% |
| Anxiety | -27% |
| Burnout | -28% |
| Sleep problems | -20% |
The wellbeing improvements weren't just self-reported. Participants' heart rate variability—a physiological marker of stress—showed measurable improvement by the trial's third month.
[!INSIGHT] The mental health benefits extended beyond work. Employees reported spending 22% more time exercising and 27% more time with their children. One participant described it as "getting my life back."
Critics had argued that a four-day week would hurt women disproportionately, as they already carry more unpaid domestic labor. The data showed the opposite: women in the trial reported greater improvements in life satisfaction and job satisfaction than men. The extra day allowed them to distribute domestic tasks more evenly across the week.
The Business Case, Quantified
For CFOs and business owners, the trial offered hard numbers on the economics of shorter weeks.
Recruitment and retention savings: With turnover dropping by 57%, companies saved an average of £12,000 per employee in recruitment, onboarding, and lost productivity costs. For a 100-person company, that's £1.2 million annually.
Sick leave reduction: The 65% drop in sick days translated to approximately 5.3 additional productive days per employee per year—ironically, more than the one day removed.
Revenue growth: Excluding companies still recovering from pandemic losses, average revenue growth across the cohort was 8.14%.
[!NOTE] Not every company thrived. The three that exited the trial cited client service challenges—one was a customer support firm with 24/7 obligations, another was in manufacturing with rigid production schedules. The model worked best for knowledge work, professional services, and creative industries.
The Global Domino Effect
The UK trial wasn't isolated. Similar experiments in Iceland (2015-2019), New Zealand (2020), and the United States (2022) produced comparable results.
Iceland's trials, involving 2,500 public sector workers, led to 86% of the country's workforce now having contracts guaranteeing shorter hours or the right to request them. Spain is currently running a €50 million government-backed pilot with 200 companies. Japan, facing chronic overwork, has seen Microsoft Japan's four-day experiment boost productivity by 40%.
“*"We're not talking about a fringe idea anymore. We're looking at a genuine shift in how advanced economies structure work.”
The European Parliament debated the four-day week in late 2022, with a non-binding resolution calling for EU-wide studies. Belgium's government has already given workers the legal right to request a four-day schedule.
What Comes Next
The four-day workweek won't become universal overnight. Manufacturing, healthcare, and customer-facing industries face structural hurdles. Small businesses worry about coverage gaps. Some employees genuinely prefer five shorter days.
But the trial's success has shifted the burden of proof. The question is no longer "Can a four-day week work?"—it's "Why are we still pretending five days is optimal when the evidence says otherwise?"
Sources: 4 Day Week Global UK Trial Results (2023), Cambridge University Research Report, Boston College Work-Family Policy Study, VoucherCloud Office Worker Productivity Survey (2019), Autonomy Institute Analysis
