Most professionals work Monday through Friday from 9 a.m. to 5 p.m. But why is that? Who decided we should work 40 hours a week? Is it a magic number that leads to productivity in the workplace and happiness at home, or is it just a carryover from the days when most people worked in manufacturing?

Is 40 hours a week too much, too few, or just right? It’s an important question for HR professionals to ask. The schedule your office maintains can have major impacts on engagement, productivity, and turnover, and there’s more than 100 years of evidence to prove it.

History of the eight-hour workday and 40-hour workweek

“Eight hours labor, eight hours recreation, eight hours rest.” This is a phrase coined in 1817 by Robert Owen—an 18th century Welsh mill owner and labor rights activist.

Owen was just one of the many activists and labor union groups who advocated for better working conditions after the Industrial Revolution. In the 1800s, it was common for people in manufacturing to work nearly 100 hours per week: between 10- and 16-hour shifts over six-day workweeks.

Labor unions were the biggest early supporters of the eight-hour workday in the U.S. In 1866, the National Labor Union asked Congress to pass a law mandating the eight-hour workday. Although the law wasn’t passed, the discussion increased public support for the change.

By the early 1900s, many industries had adopted the eight-hour workday, but most people were still working six days a week. That continued until 1926 when Henry Ford removed one required day of work from his employees’ schedules.

Ford’s employees had been working 48 hours a week: eight-hour days and six-day weeks. Removing one day resulted in eight-hour shifts for five days a week—what we now know as the 40-hour workweek.

Ford found that his workers were actually more productive working 40 hours a week than they had been working 48 hours a week. His success with the change inspired manufacturing companies all over the country to adopt the 40-hour workweek.

In 1938, Congress passed the Fair Labor Standards Act, which required employers to pay overtime to all employees who worked more than 44 hours in a week. They amended the act two years later to reduce the workweek to 40 hours, and in 1940, the 40-hour workweek became U.S. law.

Is 40 hours a week too few?

This question is the only one with a definite answer, and the definite answer is no. There’s a mountain of evidence from more than 100 years of research and tests to prove it.

Back in 1913, German psychologist Hugo Münsterberg wrote:

Ernst Abbé, the head of one of the greatest German factories, wrote many years ago that the shortening from nine to eight hours, that is, a cutting-down of more than 10 per cent, did not involve a reduction of the day’s product, but an increase.

Even before Ford, manufacturers all over the globe were running experiments and discovering how shorter working hours led to increased productivity.

Münsterberg is considered the founder of applied psychology. His book, Psychology and Industrial Efficiency, is one of the earliest arguments for using psychology to find solutions to everyday problems. Since then, psychologists and researchers have put Münsterberg’s ideas into action to study nearly every aspect of the effects of working conditions.

What they’ve found is that working more than 40 hours a week benefits no one.

A 2004 report published by the CDC’s Department of Health and Human Services provides a summary of 52 applied psychology studies on the impacts of extended shifts and regular overtime. Across the board, the studies found the impacts were negative—both for employers and employees:

* People who regularly work overtime are less healthy than those who don’t. They’re more likely to gain weight, fall ill, and get injured on the job.

* People are less alert and more likely to make mistakes after the 8th hour of work.

* People who routinely work extended hours and overtime are less productive than those who work eight hours a day and 40 hours a week.

And although a century’s worth of studies have shown that extended shifts and overtime have a variety of negative consequences for both employees and employers, the average number of hours Americans work has been steadily increasing over the last several decades. A 2014 Gallup study found that 50% of full-time workers work more than 40 hours a week.

Is 40 hours a week just right?

If working more than 40 hours is definitely bad for employee health and business productivity, then were Henry Ford and President Roosevelt right? Is the 40-hour workweek ideal?

The answer to this question is less clear, but it’s a bit more interesting to consider.

First, the 40-hour workweek is rooted in industrialism. When it was established, most people worked in factories and other manufacturing facilities. They started working when they got to work and quit working when they left. Working from home or outside of business hours was impossible.

But modern advances in technology have provided today’s workers with the tools they need to work anywhere, anytime—and they do. 80% of people continue working after they leave work for the day, and 50% check their work email while they’re still in bed in the morning. On average, people work an extra seven hours a week outside of the office.

Second, most manufacturing employees were paid an hourly rate, so they qualified for overtime pay. This was a disincentive to employers for requiring overtime because it hit them where it hurts—in the pocket.

But many office professionals today are salaried and don’t qualify for overtime. Though 59% of the U.S. workforce is paid hourly, the majority (70%) of hourly employees are under 30. Only 16% of hourly workers are in their 40s, 50s, and 60s. As people gain more experience in their careers and industries, they’re more likely to become salaried employees.

Finally, when the 40-hour workweek was established, two-income households were rare. Only 15.2% of married women were employed in 1940. But as of 2012, 60% of households had dual incomes.

When both members of a couple work, it leaves less time for children, chores, errands, food preparation, and everything else that must occur outside of working hours.

Society is different now than it was when the 40-hour workweek was established. Knowledge workers are more common than manufacturing workers. People can—and do—work outside of the workplace. People have less time to enjoy their lives because the eight hours they have each day for fun are filed with chores and errands—more rote tasks to handle.

This has led some people to claim that the 40-hour workweek is too long.

Is 40 hours a week too much?

There are a few studies that have shown employees are happier, healthier, and more productive when they work less than 40 hours a week.

* During the first two months of 1974, government officials in the United Kingdom limited the workweek to three daysin an attempt to save energy. Though people were working two fewer days a week, production only dropped 6%. People worked fewer hours, but they were more productive and less likely to miss work.

* From 2000-2008, the French government limited the maximum working hoursper week to 35. In a survey of French employees, more than half said they were happier working reduced hours and more able to achieve a balance between work and life.

* From 2015-2017, a Swedish nursing home conducted a two-year experimentwhere its nurses switched from working eight-hour days to working six-hour days for the same pay. During this time, sick leave dropped by 10%. Nurses who were part of the trial claimed they were healthier, more energetic, and more alert.

So there is some evidence that the 40-hour workweek is too long. It’s not enough to come to a definitive conclusion, but it’s certainly enough evidence for HR professionals to consider the potential benefits of reducing the number of hours in the workweek for their companies.

Finding the perfect full-time schedule for your company

As an HR professional, you’re in the perfect position to advocate for changes to the typical full-time schedule. You have all of the most compelling statistics about absences, turnover, and engagement—the things that signal change is needed. These statistics can be used to encourage company leaders to experiment with alternative working schedules.

While you probably don’t want to go in asking for a 21-hour workweek, there are some more reasonable things you can propose that will allow you to measure the impacts of changes over time:

* Cut the workweek back to 35 hours.Let people leave at lunch on Friday, and keep an eye on changes in productivity. If—like most people—they work an average of seven hours a week outside of work, cutting back the workweek will simply get them closer to a schedule that maximizes productivity.

* Consider moving to a four-day workweek.If leaders are against reducing hours, propose a four-day, 10-hours per day schedule. When Utah did this for public employees in 2008 and 2009, people were more productive and less likely to miss work, and these benefits ultimately saved the state more than four million dollars.

* Let people decide when they work.Some people are most productive in the morning. Others are most productive late at night. Consider letting people set their own schedules and work during the times when they’re most aware and energetic. If necessary, set aside a couple of hours in the middle of the day where everyone must be available.

In any of these scenarios, make sure to give employees the option to accept or decline the changes—especially if changes in money are involved.

While you may not be able to get everyone on board up front, if you can get just a few people to participate, you’ll have data to collect. And people may change their minds later when they see coworkers enjoying their new schedules.

HR should define the perfect workweek

How many working hours a week is too much? Unfortunately, it’s not a question that research has answered. We know the effects of working 50 hours a week are negative; anything over 40 makes people less productive overall. But is 40 the magic number, or is it outdated—a contributing factor to low national engagement and productivity levels?

HR professionals must carry the torch for this issue. Many of the disadvantages of employees working too many hours fall on your shoulders. Overworked employees lead to higher turnover, more injuries, disengagement, lower productivity, and more health issues—all of which increase your workload.

If you can prove that others don’t need to work so many hours to get important work done, you may eventually find that all of that overtime you’re putting in is unnecessary as well.


Jessica Greene writes for Spoke.