Microsoft (MSFT 1.07%) tested a four-day workweek over the summer, and workers may be very happy about the results. As part of a program in Japan called "Work-Life Choice Challenge," the technology giant closed its offices in the country every Friday in August, giving all employees an extra day off each week.

That cut the time that staff spent in the office by 20% (hours were not changed on the remaining four workdays). The results were encouraging: Productivity, as measured by sales per employee, increased by nearly 40%, according to a recent press release from the company.

This was a very limited test, and the same results might not be duplicated if done in Microsoft offices where coding, not sales, is the main focus. Still, it does show that when rules are put in place to make an office efficient, less can be more.

The Microsoft sign at its campus in Redmond, Washington

Microsoft has tested a four-day workweek at one office. Image source: Microsoft.

How did the test of the four-day workweek work?

Microsoft enacted some rules. Meetings, for example, were suggested to be no longer than 30 minutes, with invitation lists more tightly scrutinized. In addition, physical meetings were largely abandoned for digital ones on the company's own Teams meeting app.

Most employees in the nearly 2,300-person office said the changes affected them (90%). Workers overwhelmingly liked the change, with 92% saying they were happy with the shorter workweek. The company also noted in its press release that the shorter workweek saved it 23% in electricity, and 59% fewer pages were printed.

Can a four-day workweek work for every company?

Workplace changes tend to happen when a major company offers something new. Just a few years ago it was not all that common for people to be able to spend part of their time working from home. Major tech companies led the way in adopting work-from-home policies as a way to retain and attract people in high-demand coding positions.

Microsoft has not made any plans to test a four-day workweek in the U.S. Doing so across the whole company presents special challenges. Some departments -- like customer service -- can't simply close for part of the week. That might mean that departments would have to offer a rolling three-day weekend where some workers get Monday off and others get Friday. There are other logistical concerns to work out as well.

However, it's clear from the Japanese test that employees will work harder and focus more if they get the perk of only working four days a week. This type of test, while not yet common, is part of a growing movement to focus on work-life balance. Part of doing that involves looking more at outcomes and work product than at hours spent at a desk.

Microsoft has shown that a four-day workweek can work. A lot more testing will be needed to see how it might look across the entire company, or how other companies might implement it. What's clear, however, is that once workers know this may be an option, they will almost certainly clamor for it. That could lead to smaller companies offering shorter workweeks as a way to attract employees who otherwise might not be interested.

A four-day workweek might be even more efficient than a five-day workweek. That may seem hard to believe -- but people can be motivated by a prize, and an extra day off each week is certainly a factor that should push people to be more productive when they are at the office.