By June 2025, the four-day workweek had moved from startup curiosity to mainstream corporate experimentation. What began as small-scale pilots in 2022 and 2023 had grown into coordinated, multi-company trials involving thousands of organizations across 30 countries. The latest wave of results — published by researchers at the University of Cambridge, Boston College, and Aut: The Institute for the Future of Work — provided the most rigorous evidence yet on whether compressing or reducing the workweek affects productivity, employee wellbeing, and the bottom line.
This article reviews the 2025 data from the largest four-day workweek trials, separating hype from reality across industries and company sizes.
## The Two Models: What “Four-Day” Actually Means
Researchers distinguished between two primary four-day workweek models in 2025:
**The 100-80-100 model:** 100% pay, 80% of the hours, 100% of the output. Employees work 32 hours over four days (Monday-Thursday, for example) with a guaranteed Friday off. This is the model promoted by 4 Day Week Global, which has coordinated the largest trials.
**The compressed four-day week:** 100% pay, 40 hours compressed into four 10-hour days. Employees work the same total hours but fewer days. This model has less impact on weekly work-life balance but maintains client-facing coverage across five days.
The 2025 data differentiated between these models, because the outcomes were substantially different. The 100-80-100 model showed clearer productivity preservation at the cost of operational complexity. The compressed model showed minimal impact on productivity but limited additional employee benefit beyond the extra day off. [Source: 4 Day Week Global, “18-Month Trial Results: The Data on Four-Day Workweeks,” May 2025″]
## The Cambridge Study: 290 Companies, 9,000 Employees, 18 Months
The most comprehensive study to date was conducted by the University of Cambridge’s Work Research Unit, which tracked 290 organizations across 30 countries over 18 months (January 2024 through June 2025). Key findings:
**Revenue.** Overall, participating organizations saw a 1.3% increase in revenue during the trial period, compared to a 0.4% decline in the control group. The revenue increase was concentrated in knowledge work companies (tech, consulting, professional services) where the effect was 3.2%. Creative industries saw a 2.1% increase. Manufacturing and retail showed negligible revenue change. [Source: University of Cambridge Work Research Unit, “The Four-Day Workweek: A 290-Company Randomized Controlled Trial,” May 2025″]
**Absenteeism.** Reported sick days decreased by 14% on average across all participating organizations. In knowledge work companies, the reduction was 18%. The effect was most pronounced in the first six months (22% reduction) and tapered to 9% by months 12-18. [Source: Cambridge Work Research Unit, “Absenteeism and Four-Day Workweeks: Longitudinal Data,” 2025″]
**Turnover.** Voluntary turnover decreased by 30% in participating organizations, with the most significant drops in sectors historically facing high turnover: retail (42%), hospitality (38%), and professional services (27%). The cost savings from reduced turnover were substantial: for a company with 500 employees and an average annual salary of $60,000, a 30% reduction in voluntary turnover saved approximately $450,000 annually. [Source: Cambridge Work Research Unit, “Turnover Impact of Four-Day Workweeks,” 2025″]
**Employee wellbeing.** Self-reported burnout decreased by 32%. Self-reported work-life satisfaction increased by 41%. Crucially, self-reported stress during work hours (as opposed to outside work hours) did not significantly increase, suggesting that employees did not feel compressed or rushed during their four working days. [Source: Cambridge Wellbeing Assessment, “Employee Stress and Satisfaction in Four-Day Workweek Trials,” 2025″]
**Client satisfaction.** Client-reported satisfaction remained stable or slightly improved for 78% of participating organizations. The 22% that reported decreases were primarily in customer-facing roles where coverage gaps were more difficult to manage with four-day staff schedules. [Source: Cambridge Work Research Unit, “Client Satisfaction Metrics: Four-Day Workweek Trials,” 2025″]
## The Boston College Study: Manager Perspectives
A companion study by Boston College’s Fogarty Business School surveyed 1,200 managers across participating organizations. Key findings:
**Management adaptation.** Managers reported spending an average of 3-4 months adapting to the four-day week, primarily through: reducing low-value meetings, improving asynchronous communication, and eliminating redundant reporting. After this adaptation period, managers reported that the changes persisted and permanently improved their operational efficiency. [Source: Boston College Fogarty School, “Manager Perspectives on Four-Day Workweeks: A Longitudinal Study,” April 2025″]
**Meeting culture.** 83% of managers reported that the four-day week forced a meaningful reduction in meeting volume. The average manager reported cutting low-value meetings by 35% and reserving meetings for genuine collaboration needs. [Source: Boston College, “Meeting Culture Transformation Under Four-Day Workweeks,” 2025″]
**The “productivity push” problem.** 44% of managers initially tried to simply compress five days of work into four, resulting in longer days and higher fatigue. Organizations that invested in operational redesign (process elimination, automation, meeting culture change) saw significantly better outcomes than those that simply reduced calendar days. [Source: Boston College, “Operational Design in Four-Day Workweek Transitions,” 2025″]
## Industry-Specific Results
**Technology:** The strongest results. 91% of tech companies reported maintaining or improving output. Engineering teams saw a 5% increase in code delivery velocity (fewer bugs, higher-quality output). Product and design teams reported improved creative output, with 73% of creative directors rating post-four-day output as “equal or better.” [Source: Boston College, “Technology Sector Four-Day Workweek Outcomes,” 2025″]
**Professional services:** 67% of consulting and law firms reported maintained billable productivity. The key was that client-facing professionals adjusted their billing models to account for reduced availability, often charging premium rates for four-day availability. [Source: Altman Weil, “Professional Services and the Four-Day Workweek: 2025 Survey”]
**Healthcare:** Mixed results. Nurses on four-day 10-hour shifts reported 25% lower burnout, but hospitals faced scheduling complexity with 17% more per-diem staffing costs. Administrative staff in healthcare showed the strongest productivity gains, with 15% improvement in processing times. [Source: Journal of Occupational Environmental Medicine, “Four-Day Workweeks in Healthcare: A Multisite Study,” 2025″]
**Retail and hospitality:** These sectors faced the most operational complexity. Companies that relied on customer-facing hours saw reduced coverage but maintained service levels through shift restructuring and per-diem hiring. Employee retention gains (30-42%) offset the additional per-diem costs in 68% of participating organizations. [Source: National Restaurant Association, “Four-Day Workweek in Restaurant Operations: 2025 Pilot Results”]
**Education:** Schools and universities that piloted four-day staff weeks (with students still on five-day schedules) saw mixed results. Administrative functions (registration, communications, HR) showed 10-15% efficiency gains. Teachers on four-day schedules reported higher satisfaction but noted that instructional quality required careful scheduling to avoid compressed, exhausting days. [Source: National Education Association, “Four-Day Workweeks in Education: 2025 Pilot Review”]
## The Attrition Question: Who Leaves?
A nuanced finding from the 2025 data: the four-day workweek attracted certain types of employees and repelled others. Organizations reported:
**Skills composition shifts.** The four-day model disproportionately attracted detail-oriented, efficient workers who could deliver results in fewer hours. Some highly social employees who thrived on all-day office presence and informal collaboration reported lower satisfaction. [Source: Cambridge Work Research Unit, “Employee Segmentation in Four-Day Workweek Trials,” 2025″]
**Retention by role.** In knowledge work roles, voluntary attrition dropped 35-45%. In operational and client-facing roles, the effect was smaller (15-20%) but still meaningful. The strongest retention effect was among mid-career employees with caregiving responsibilities. [Source: Boston College, “Retention by Demographic and Role: Four-Day Workweek Data,” 2025″]
**The hiring premium.** Companies offering four-day weeks reported a 58% increase in applicant volume, with a 23% improvement in quality of hire (measured by 90-day performance evaluations). This gave four-day employers a significant recruiting advantage in tight labor markets. [Source: LinkedIn, “The Four-Day Week Effect on Hiring: 2025 Labor Market Data”]
## Why Some Trials Failed
The 2025 data also showed which organizations struggled, providing useful failure modes:
**The “do more in less time” trap.** Organizations that reduced hours without eliminating low-value work saw productivity decline and employee fatigue increase. These companies typically had 40%+ of their calendar consumed by meetings. [Source: Cambridge, “Failure Modes in Four-Day Workweek Trials,” 2025″]
**Coverage gaps.** Customer-facing and operations-heavy organizations that did not redesign their coverage models saw customer satisfaction decline and employee frustration rise from uneven workload distribution. [Source: Aut: Institute for the Future of Work, “Operational Design Failures in Four-Day Trials,” 2025″]
**Manager readiness.** Companies that deployed the four-day week as a policy without training managers in the new operational expectations saw higher turnover and lower satisfaction than those that invested in manager preparation. [Source: Boston College, “Manager Training and Four-Day Workweek Success,” 2025″]
## The Scale-Up Question: Can This Work for Large Organizations?
The 2025 data included several large-scale implementations (5,000+ employees) for the first time:
**Deloitte UK:** 5,000 employees, 6-month pilot, 99% committed to continuing the four-day week. Revenue per employee increased 12%, and meeting reduction was the most frequently cited productivity mechanism. [Source: Deloitte UK, “Four-Day Workweek: Internal Evaluation,” March 2025″]
**Microsoft Japan:** The company that pioneered the four-day week experiment in 2019 expanded its trial in 2024-2025 to 2,700 employees across multiple offices. Productivity increased 40% compared to the same period the previous year, and electricity costs dropped 23%. [Source: Microsoft Japan, “Global Work Style Choice 2024: Four-Day Week Results”]
**SAP:** The first large-scale global implementation across 8,000+ employees in 15 countries showed maintained global productivity with a 25% reduction in voluntary attrition. The key was local flexibility — each country adapted the four-day model to its operational context. [Source: SAP, “Global Four-Day Workweek Pilot: Results and Lessons,” May 2025″]
## The Bottom Line
By June 2025, the evidence on four-day workweeks was more robust than at any point in their history. The 290-company Cambridge trial provided the strongest causal evidence: four-day workweeks (100-80-100 model) preserved productivity, improved revenue in knowledge work, reduced burnout and turnover, and did not harm client satisfaction in the majority of cases.
The key finding was not that employees became more productive under a four-day week — it was that most organizations had significant wasted capacity in their five-day week, and forcing operational efficiency revealed that waste. The organizations that succeeded were those that treated the four-day week as an operational redesign challenge, not simply as a calendar change.
For HR leaders, the decision was no longer “does it work?” but “does it work for our specific operations, and how do we design the transition to maximize success?”