The Four-Day Work Week in Tech: Pilot Results, Productivity Data, and Why More Companies Are Making It Permanent

The Evidence Is In

The largest controlled trial of the four-day work week in history concluded with a result that surprised even its advocates. The UK pilot, coordinated by 4 Day Week Global and researched by Boston College, the University of Cambridge, and Autonomy, enrolled 61 companies and approximately 2,900 employees for a six-month trial from June to December 2022. The results: 92% of participating companies chose to continue the four-day week after the trial ended, with 18 confirming the change as permanent. Revenue across participating companies remained stable during the trial itself, rising by 1.4% on average. Employee turnover dropped by 57%. Sick days decreased by 65%. And 71% of employees reported reduced levels of burnout.

A 2024 follow-up found that 89% of those companies were still operating a four-day week more than a year later, with 31 firms — over half the original cohort — having made the policy permanent.

Then, in July 2025, the largest and most rigorous study to date was published in Nature Human Behaviour. Covering 141 companies and 2,896 workers across six countries — Australia, Canada, Ireland, New Zealand, the United Kingdom, and the United States — the study found that 90% of participating companies retained the four-day arrangement after the six-month experiment. Burnout decreased by 0.44 points on a 1-5 scale, job satisfaction increased by 0.52 points on a 0-10 scale, and employees reported measurable improvements in both mental and physical health. The study provided the kind of peer-reviewed, multi-country evidence that earlier pilots could not.

These numbers have propelled the four-day work week from a fringe experiment to a serious policy discussion. By 2025, 4 Day Week Global had run trials across the United States, Australia, Ireland, South Africa, Brazil, Portugal, and Germany. In Germany, a 2024 pilot of 45 companies — coordinated by Berlin consultancy Intraprenor and studied by the University of Munster — found that 73% of participating firms planned to make the shortened week permanent or extend the experiment. National governments have taken notice: Belgium passed a law in 2022 giving workers the right to compress their work week into four days at the same total hours. Iceland conducted landmark public sector trials (over 2,500 workers, 2015-2019) that reduced working hours to 35-36 per week; trade unions used the results in collective bargaining, securing shorter hours for nearly 90% of Iceland’s workforce. Spain launched a government-funded trial with financial support for small and medium-sized enterprises. Scotland committed 10 million GBP to pilot programs and began a civil servant trial in early 2024. The UAE shifted to a 4.5-day work week for government employees in 2022, and Tokyo’s metropolitan government introduced a four-day option for its 160,000 workers in April 2025 to support families and address Japan’s declining birth rate.

More than 2.7 million UK workers — nearly 11% of the workforce — now report working a four-day week as of 2025.

Tech companies have been at the vanguard of adoption. Buffer began experimenting with the four-day week in May 2020 and made it a permanent policy by early 2021. Kickstarter completed a successful pilot in 2022 and formalized the policy, though the company faced a labor dispute over the arrangement in late 2025. Wildbit, the company behind Postmark and Beanstalk, has operated on a four-day week since 2017 and is one of the longest-running examples in the industry. Elephant Ventures, a data engineering consultancy, reported a 20-30% productivity boost after switching to a compressed four-day model (4 x 10 hours) and adopted the schedule permanently. The pattern across these companies is broadly consistent: output stayed the same or increased, while employee satisfaction, retention, and well-being improved.

Not every adoption has lasted. Bolt, the fintech company, made the four-day week permanent in January 2022 to widespread media coverage — but quietly reversed the policy later that year amid layoffs that cut roughly a third of its workforce. UK hosting firm Krystal also ended its trial after experiencing service backlogs. These reversals illustrate a critical point: the four-day week works best when paired with deliberate operational restructuring, not when it is simply layered onto existing processes.

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Implementation Models: Not All Four-Day Weeks Are Equal

The four-day work week is not a monolithic concept. Companies implement it through several distinct models, each with different trade-offs for different types of work and different organizational cultures.

The reduced-hours model (4 x 8 = 32 hours per week) is the purest form and the one tested in most formal trials, including the UK pilot and the 2025 Nature study. Employees work four standard eight-hour days and receive a three-day weekend every week. Pay does not change. The premise is that knowledge workers — particularly in tech — are not actually productive for 40 hours per week. Studies consistently show that meaningful cognitive output peaks at four to six hours per day for most knowledge workers, with the remaining time consumed by meetings, context-switching, email, and low-value tasks. The reduced-hours model forces organizations to eliminate waste: cutting unnecessary meetings, reducing email volume, and protecting focused work time.

The compressed-hours model (4 x 10 = 40 hours per week) maintains total working hours but compresses them into four longer days. This model is more common in industries with coverage requirements — customer support, operations, healthcare — and is the model that Belgium’s 2022 law enables. The benefit is a three-day weekend; the cost is longer days that can exacerbate fatigue. Research from the Autonomy think tank suggests that the productivity benefits of the compressed model are smaller than the reduced-hours model, because longer days reduce per-hour productivity. Elephant Ventures used this model and reported gains, but it is generally considered less transformative than true hour reduction.

The staggered model divides the company into two groups: Group A takes Monday off, Group B takes Friday off. This ensures five-day coverage for clients and external stakeholders while giving every employee a four-day week. Wildbit uses a version of this approach for its customer support team. The advantage is minimal disruption to client-facing operations; the disadvantage is that the full team is only together Tuesday through Thursday, which can complicate collaboration.

The seasonal or cyclical model implements the four-day week during certain periods but returns to five days during high-intensity periods. Basecamp (now 37signals) is the best-known example: the company operates on four-day, 32-hour weeks from May through August every year, and has done so for over a decade. This hybrid approach is popular among companies that face uneven workload distribution throughout the year, though it delivers less consistent well-being benefits than a year-round policy.

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Which Tech Roles Benefit Most?

The four-day work week’s impact varies by role type, and understanding this variation is critical for implementation.

Individual contributors in engineering, design, and data science report the highest benefits. These roles depend on deep focus — sustained periods of uninterrupted concentration where complex problem-solving occurs. The five-day work week, with its meetings spread across every day, fragments this focus. A four-day week, when combined with meeting-free policies on one or two of those days, can provide more total deep-focus hours than a five-day week despite fewer total hours. Buffer’s engineering team reported that their deep-focus time per week actually increased after switching to four days because the reduced schedule forced the elimination of status meetings and check-ins that provided little value.

Product managers and engineering managers report more mixed results. These roles are inherently collaborative, involving cross-functional meetings, stakeholder alignment, and communication that scales with organizational complexity. Compressing these interactions into four days can create “meeting-heavy” days that leave no time for the strategic thinking and planning that managers also need. Companies that have succeeded with four-day weeks for managers typically pair the schedule change with aggressive meeting reduction — eliminating standing meetings, replacing synchronous status updates with async tools (Loom, Notion, Slack updates), and establishing “no-meeting” days.

Customer-facing roles — support, sales, customer success — face the greatest implementation challenge. Customers expect five-day (or seven-day) availability, and a four-day internal schedule must not degrade the customer experience. The staggered model (different days off for different team members) and the use of AI-powered support tools (chatbots, automated ticket routing, knowledge bases) are the primary solutions. Wildbit found that faster, higher-quality support during four focused days can actually improve customer satisfaction compared to lower-energy support spread across five.

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The Skeptics’ Case

Despite the compelling trial data, significant objections to the four-day work week deserve serious engagement. The strongest skeptical arguments are not about laziness — they are about selection bias, competitive dynamics, and applicability.

Selection bias in trials is the most methodologically important critique. Companies that voluntarily opt into a four-day work week trial are, by definition, organizations whose leadership already believes it might work. They tend to be well-managed, innovative, and operating in knowledge-work sectors. The 2025 Nature study acknowledged this limitation explicitly. The trial results may reflect the quality of participating companies rather than the inherent benefit of the four-day week. The question is whether the same results would hold at a company with poor management, unclear priorities, and endemic inefficiency — arguably, the companies that most need a productivity intervention.

Competitive dynamics create a game-theory concern. If Company A adopts a four-day week and Company B does not, and both operate in the same market, does Company B gain an advantage from 20% more total work hours? The trial data suggests no, because the additional hours do not translate to additional productive output. But this argument is difficult to prove in competitive markets with real deadlines, especially in consulting, agency, and client-service models where billable hours directly translate to revenue.

Industry applicability is the most legitimate concern. The four-day work week trials have overwhelmingly enrolled knowledge-work companies in professional services, tech, and creative industries. Whether the model works for hardware companies with manufacturing schedules, startups in hypergrowth mode with existential deadlines, or companies in markets with deeply embedded long-hours cultures remains genuinely uncertain. The reversals at Bolt and Krystal — companies where the operational restructuring required to make the policy work was underestimated — offer real cautionary evidence.

The startup objection is particularly resonant in tech. Many founders and investors argue that the early stages of a company require intensity that a four-day week cannot provide. Counterarguments point to Wildbit, which has operated on a four-day week since 2017 while shipping successful products, and to Basecamp/37signals, which has maintained seasonal reduced hours for over a decade alongside consistent product output. These examples suggest that intensity is about focus rather than hours — though critics note these are established, profitable companies, not pre-revenue startups burning cash.

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Sources & Further Reading

• Nature Human Behaviour – Four-Day Workweek Study (2025)
• 4 Day Week Global – UK Pilot Results
• Autonomy – The Results Are In: The UK’s Four-Day Week Pilot
• 4 Day Week Global – Germany 2024 Pilot Results
• Buffer – Four-Day Work Week Data
• Wildbit – Four-Day Work Week
• Autonomy – Iceland’s Shorter Working Week
• Scientific American – Biggest Trial of Four-Day Workweek