The 4-Day Work Week That Actually Works for Women
Let’s face it, the traditional 5-day work week aligns with male biology and energy patterns. It’s no surprise, therefore, that women who work from home or have flexible positions often report increased well-being and efficiency. They can adjust their workload to how they feel - working to a 28 day cycle rather than a 24 hour one.
Microsoft Japan found that switching to a four-day workweek resulted in a 40% boost in productivity, while research highlights that flexible work hours (over flexible work locations) are crucial for retaining and engaging women in the workforce. Lack of flexibility around working hours is now the top reason women want to leave their jobs.
Women are 5% more likely than men to favor a four-day workweek for potential savings on childcare expenses. This gender difference underscores how flexible work arrangements can particularly benefit women by reducing childcare costs, thereby supporting a more inclusive and equitable workplace.
Key takeaways
Microsoft Japan saw 40% productivity gains with a 4-day work week, proving shorter weeks can boost output rather than reduce it.
Flexible work hours are now the top reason women leave jobs - making the 4-day week crucial for retention.
Women are 5% more likely than men to favor 4-day weeks for childcare cost savings, showing unique benefits for female workers.
Why traditional work weeks don't serve female biology
The 40-hour, five-day work week isn't rooted in biological science or productivity research. It was established in 1938 as the norm at a time when the workforce was predominantly male with homemaking wives. But decades later, everything has changed. Women now constitute half the workforce, yet we're still operating within a system designed for consistent, 24-hour energy cycles - the male hormonal pattern.
Research investigating workplace flexibility by gender revealed that women showed greater interest as compared to men in prioritizing workplace flexibility. This isn't coincidental - it reflects fundamental biological differences that affect work performance and wellbeing, alongside the additional roles that many women also carry as part of their family.
Women operate on approximately 28-day cycles with distinct phases that affect energy, focus, creativity, and social skills. Expecting women to show up with identical energy and capabilities every single day isn't just unrealistic - it's setting them up for burnout.
Research indicates that flexible work arrangements lead to reduced turnover rates, enhanced worker satisfaction and increased organisational commitment. Organisations are advised to prioritise the implementation of Flexible Work Arrangements to enhance employee retention, work happiness, and general well-being.
This biological mismatch explains why so many women struggle with traditional productivity advice. The "rise and grind" mentality assumes energy levels remain constant, but women's natural rhythms include both high-energy periods perfect for creative breakthroughs and lower-energy phases ideal for reflection and planning.
Deloitte research shows that an organization's ability to offer women flexibility around when their work gets done is a top lever of engagement and retention—even more than where they work. The evidence is clear: when women can work with their natural rhythms instead of against them, everyone benefits.
4-Day Week models that work for cyclical productivity
But what different models exist for supporting flexibility at work, or a 4 day work week?
Compressed Schedule Model
The most common approach involves working four 10-hour days instead of five 8-hour days. While this maintains the same total hours, it provides a full extra day for recovery, personal projects, and life management. For women, this additional day can be perfectly timed around lower-energy cycle phases.
56% of employees prefer working 40 hours across 4 days rather than 5. This shows that over half of the workforce is open to a more concentrated work schedule, indicating that businesses adopting this model may benefit from increased employee satisfaction and reduced burnout.
This model works particularly well during the luteal phase when energy naturally decreases but attention to detail increases. The longer days can be front-loaded during higher energy phases, with the extra day off providing crucial recovery time.
Flexible Four-Day Model
This approach reduces total working hours to 32 per week across four days, maintaining full pay. Microsoft Japan closed its offices every Friday in August and found that labor productivity increased by 39.9% compared with August 2018. The experiment recorded largely positive feedback from employees, too, with 92.1% saying they liked the four-day workweek.
Microsoft Japan became more efficient in several areas, including lower electricity costs, which fell by 23%. And as its workers took five Fridays off in August, they printed nearly 60 percent fewer pages.
The benefits extended far beyond productivity metrics. Microsoft Japan is now planning to conduct a similar work-life challenge this winter, aimed at encouraging greater flexible working.
Cycle-Synced Scheduling
The most sophisticated approach aligns work intensity with menstrual cycle phases. During high-energy phases (follicular and ovulatory), women might work more intensively. During lower-energy phases (late luteal and menstrual), they might take their extra day off or work reduced hours.
This model requires cycle tracking and planning, but offers the most personalized approach to productivity optimization. Phase's app can support this model by helping women identify their energy patterns and plan accordingly.
Real results: Companies getting it right
Microsoft Japan's trial resulted in a productivity boost of 40%. The Microsoft trial roughly doubled Perpetual Guardian's productivity gain, which had previously seen impressive results from their own four-day experiment.
Perpetual Guardian, a New Zealand trust management company, announced a 20% gain in employee productivity and a 45% increase in employee work-life balance after a trial of paying people their regular salary for working four days. Last October, the company made the policy permanent.
The benefits aren't limited to large corporations. 92% of companies in the UK's world's biggest four-day workweek experiment say they're continuing with the four-day week permanently. The results speak for themselves.
Tyler Grange, a UK environmental consultancy: Productivity increased by 22%, job applications are up 88%, absenteeism is down by 66%, their carbon footprint is down with people driving less for work, and employees are less tired and happier.
On the employee side, 90% said they definitely want to continue with a four-day week, 55% reported an increase in their ability at work, and 15% said no amount of money would make them go back to a five-day schedule. Reduced work stress and extra personal time led to several positive health and well-being outcomes: lower stress, better mental health, less negativity, more exercise and an easier time sleeping.
How to propose this at your workplace
Build your business case
Start with the data. Microsoft Japan's 40% productivity increase and reduced operational costs provide compelling evidence. Focus on outcomes, not hours worked.
Key arguments to include:
Productivity often increases when working hours decrease
Reduced absenteeism and turnover save significant costs
Enhanced employee satisfaction improves retention
Lower overhead costs from reduced office usage
Address common concerns
"But we need to be available to clients": Counter this by proposing staggered schedules or emphasizing improved productivity during working hours. Microsoft also reduced the time spent in meetings by implementing a 30-minute limit and encouraging remote communication.
"What about workload management?": Address this by proposing pilot programs with clear productivity metrics. The successful experiments use a 100-80-100 model: workers get 100% of the pay for working 80% of the time in exchange for delivering 100% of their usual output.
Suggest a trial period
Just as Microsoft Japan did, starting with a pilot can be a good way to dip your toes into the reality of a four-day workweek while identifying potential barriers and how to get around them.
Propose a 3-6 month trial with:
Clear productivity metrics
Regular check-ins and feedback sessions
Measurable outcomes for both employees and business goals
Flexibility to adjust the model based on results
Building your personal 4-Day system (even without official support)
Maximize your existing flexibility
75% of employees say the ability to work flexibly and from anywhere is critical for their engagement. 27% of employees cite inflexible working hours as a reason for quitting their job, showing the importance of autonomy in engagement.
Even within traditional structures, you can optimize your schedule:
Front-load work during high-energy cycle phases
Use slower periods for administrative tasks and planning
Negotiate remote work days during lower-energy phases
Block time for deep work during peak focus periods
Create boundaries
Among women who have actually left their employers in the past year, the top reason was insufficient pay, followed by a lack of flexible working and poor work/life balance.
Establish clear boundaries around:
When you're available for meetings and calls
Which days you work from home versus the office
How you manage energy-intensive tasks throughout your cycle
Your need for recovery time during certain cycle phases (learn more about rest here)
Track and optimize
The available evidence supports that work flexibility in terms of location and work hours gives workers some sense of job control, improves their engagement, and increases their job satisfaction, thereby improving their health and well-being.
Use tools like Phase to:
Monitor your energy patterns across cycle phases
Plan projects around your natural productivity peaks
Anticipate lower-energy periods and plan accordingly
Demonstrate your productivity improvements over time
The gender equality benefits
A shortened workweek could lead to better gender parity of household work: The time men spent caring for their children increased by more than double that of women. Men, meanwhile, were more likely to use their newfound time to contribute more to housework and child care.
A recent report argued that it could help women by shifting childcare responsibilities to balance more evenly between women and men. It would also allow more flexibility for parents to spend their extra day off running necessary errands and dealing with other family matters — allowing them to be more focused and productive when they are working.
As it's women who are more likely to quit their job or work part-time, a shorter working week would free up men's time to do more care work so women can increase their paid hours or enter the work market if they wish to.
The financial reality
With the rising cost of living prices as well as increases in childcare costs, a four-day week could alleviate much of the pressure working parents face financially. A four-day week, where there is no loss of pay, could make a significant difference to a household budget and could even stop some families from falling into debt. The fact is, childcare costs and commuting can run into the thousands - so an opportunity to reduce costs is welcome if a household can make significant savings.
The numbers are compelling: 58% of people prefer getting a 4-day workweek instead of a pay raise. This suggests that many employees value improved work-life balance over additional income, meaning companies can attract and retain talent by offering flexible schedules even without immediate financial incentives.
The productivity revolution starts now
60% of employees would stay in a job they dislike if it offered flexible working hours, proving the importance of autonomy. 75% of employees say the ability to work flexibly and from anywhere is critical for their engagement.
The evidence is overwhelming. Companies implementing 4-day work weeks aren't just improving their bottom line - they're pioneering the future of work. A future where productivity isn't measured by hours at a desk, but by outcomes achieved. Where energy patterns are respected, not ignored. Where sustainable success replaces unsustainable hustle.
Workplace flexibility is another benefit that has expanded significantly in the past decade. Mostly in response to the pandemic, companies dramatically increased their hybrid and remote-work options. Eight in ten employees say flexibility has improved over the past ten years, and employees consistently point to greater productivity and reduced burnout.
Your cycle isn't a limitation to overcome - it's a competitive advantage waiting to be unleashed. The question isn't whether you can afford to work with your biology. It's whether you can afford not to.
The future of productivity isn't about working harder - it's about working smarter. And that starts with understanding that women's biology isn't broken - it's just different. When we design work structures that honor that difference, everyone wins.
Phase helps you map your optimal work patterns, time your most important projects, and build a career that works with your body, not against it. Track your productivity patterns across your cycle, identify your peak performance windows, and make data-driven decisions about when to tackle your biggest challenges.
Try Phase today and discover how cycle syncing can transform your approach to work and productivity.
Photo by TheStandingDesk on Unsplash
