The world's largest trial of a four-day workweek conducted in the United Kingdom has been a roaring success as an overwhelming majority of the 61 companies that participated from June to December have decided to keep going with the shorter hours after the pilot has been hailed a breakthrough for employees to be less stressed and have better work-life balance.

That was all while companies reported revenue largely stayed the same during the trial period last year and even grew compared with the same six months a year earlier, according to findings released this week.

"We feel encouraged by the results, which showed the many ways companies were turning the four-day week from a dream into a realistic policy, with multiple benefits," said David Frayne, research associate at the University of Cambridge, who helped lead the team conducting employee interviews for the trial. "We think a lot here ought to motivate other companies and industries to try it."

The university's team worked with researchers from Boston College; Autonomy, a research organization focused on the future of work; and the 4 Day Week Global nonprofit community to see how the companies from industries spanning marketing to finance to nonprofits and their 2,900 workers would respond to reduced work hours while pay stayed the same.

Not surprisingly, employees reported benefits, with 71% less burned out, 39% less stressed, and 48% more satisfied with their job than before the trial.

Of the workers, 60% said balancing work and responsibilities at home was more manageable, while 73% reported increased satisfaction with their lives. In addition, the findings show that fatigue was down, people were sleeping more, and mental health improved.

That's just what Platten's fish and chips restaurant in the English seaside town of Wells-Next-The-Sea has found, especially in the hospitality industry where people often work seven days a week.

"Everyone is focused, everyone knows what they're doing, everyone is refreshed," said Kirsty Wainwright, the restaurant's general manager, about a three-hour drive northeast of London. "What it means is that they are coming into work with a better frame of mind and passing that on to the clients and the public coming here for their meals. They're getting a greater service because the team is more engaged."

Starting the trial going into the busy season in June, Platten's, open seven days a week, found the biggest hurdle was finding a model that worked for everyone, Wainwright said.

She said they constantly communicated with employees to find what worked best, which was having the staff split into two groups, allowing one group to work two days on and another to have two days off.

The concept lets people work, have a day to do chores like cleaning the house, and "then have two days off, seeing your friends, seeing your family, doing some stuff yourself," Wainwright said. "And that's what this is all about – is just working to live and not living to work."

For companies that rolled out the shorter work hours – whether it was one less workday a week or longer hours in parts of the year and shorter hours the rest of the time to make an average 32-hour week – revenue wasn't affected, the findings say.

Revenue grew 1.4% throughout the trial for 23 companies that provided adequate data – weighted for the business size – while 24 companies saw revenue climb more than 34% from the same six-month period a year earlier.

For Platten's, "I don't think we were measuring it in terms of profitability," Wainwright said. "That's not it for us. We wanted to measure it in productivity. And actually, the productivity has gone through the roof."

For all those who participated in the trial, there was a drop in the likelihood of employees quitting, down 57% compared with the same period a year earlier, as well as those calling out sick, down 65% from a year ago, according to the findings.

Of the companies, 92% reported they would continue with the four-day workweek, with 30% saying it's a permanent change. That includes Platten's, which said it's sticking with the model permanently.

Charlotte Lockhart, co-founder, and managing director of 4 Day Week Global, said the "resounding success" of the U.K. pilot program mirrors earlier efforts in Ireland and the U.S.

Some industries can't institute shorter hours because they need workers around the clock, such as nurses and first responders. Those workers and others have been walking off the job in the U.K. recently, demanding better working conditions and pay that keeps pace with the high cost of living.

The pandemic changed how the world works, with people seeking greater flexibility to improve work-life balance.