A century ago, the five-day working week helped reshape society. It was introduced at scale by industrial pioneers to address not only worker wellbeing but also economic pressures.
US industrialist Henry Ford was among the first to give workers two full days off per week, 100 years ago this month. Ford suspected that giving workers a "weekend" would increase overall productivity - and he was correct.
Today, as advances in artificial intelligence accelerate and concerns about job security grow, a similar question is emerging. Could reducing working time again help societies adapt to these seismic changes?
The evidence increasingly suggests it can, but not in the simplistic way that is often portrayed. The four-day week is not just a workplace benefit. It is a potential tool to improve wellbeing, support families and rethink how work is distributed in society.
Research across multiple countries, including large-scale pilots in the UK and Portugal, shows that reducing working time can deliver meaningful benefits for both employees and organisations.
In a 2025 study of four-day week adoption, my colleagues and I found improvements in sleep, exercise and quality of working life. There were positive implications for both the mental and physical health of employees.
Our research showed productivity at work can also increase, alongside reductions in absenteeism and staff turnover. And it can be beneficial for an employer's social image.
However, the most important insight is not about productivity but what happens outside work. After all, time is a social resource, not just an economic one.
When people move to a four-day week, they do not simply rest more. They reallocate time in ways that have broader implications for society.
Across our research , participants said they spend more time with family and friends, engaging in community activities and investing in their physical and mental health by exercising and practising hobbies and self-care activities.
These are not trivial changes. Over time, they contribute to stronger social ties, better mental health and more resilient communities.
There are also important gender implications. Early findings suggest that reduced working time can lead to fathers being more involved in caring for their children and other domestic responsibilities. While this does not automatically solve gender inequality, it creates conditions that make more equal divisions of labour possible.
In this sense, the four-day week is not just about work. It is about how societies organise care, relationships and everyday life.
The challenge in service sectors
Critics of a four-day week often point out that it is harder to implement in service sectors such as healthcare, childcare, manufacturing, hospitality or retail. This is true, but it is not a reason to dismiss the idea.
In these sectors, work is tied to time, presence and staffing levels. Reducing working hours often requires more complex redesign, including changes to rotas, additional hiring or upfront investment. Colleagues and I have highlighted this when addressing the UK case of the NHS.
But these challenges should be seen as design problems, not impossibilities. In fact, the potential benefits to society may be even greater in these sectors. Improved wellbeing and reduced burnout among healthcare staff and care workers can translate into better quality of service and fewer mistakes.
A more important concern is inequality. If working time reductions are adopted unevenly, there is a risk that some workers will be excluded - often those in lower-paid or frontline roles. This is a valid concern, but not an argument against the four-day week. Rather, it is an argument for implementing it more thoughtfully.
Instead of asking whether all jobs can adopt the same model, the focus should be on how different forms of reduced work time can be adapted across sectors. This could include shorter daily hours, staggered schedules or phased time reductions.
The future of work
The renewed interest in reducing the amount of time we spend working is not happening in isolation. It is closely linked to broader debates about automation, productivity and the future of work.
If technological advances continue to increase productivity, a fundamental question arises: who benefits from these gains?
Historically - during the Great Depression , for example - working time reductions have been one way of redistributing those benefits. Compared with more radical proposals such as universal basic income, the four-day week offers a more direct and socially embedded way of sharing gains in productivity.
The four-day week is not a universal solution, and it will not look the same everywhere. But the evidence shows working less can go hand-in-hand with maintaining productivity.
It can also support a shift towards a society where time is valued not only as an economic input, but as a foundation for wellbeing, relationships and participation in community life.
A century after the five-day week helped define modern work, there may be another turning point on the horizon. This time, the real question is not whether we can afford to reduce working time, but whether we can afford not to.
Rita Fontinha's employer, the University of Reading, has received funding from the Portuguese Government and the Azores Regional Government to conduct academic research on four-day working week pilots.
