A Brief History of the 5-Day Workweek

Before the Weekend

For most of recorded history, the working week was six days, with one day reserved for religious observance. The Jewish Sabbath, codified in the Hebrew Bible, set aside Saturday for rest; Christianity later adopted Sunday for the same purpose, and the Quran prescribes Friday congregational prayer. Six days of labour and one of rest was the default rhythm for agrarian and early industrial economies alike. Pre-industrial workers also enjoyed dozens of saints' days and feast days scattered through the year — by some estimates, the medieval English peasant worked fewer total hours per year than the average modern office worker, simply because the calendar was riddled with holy days.

The Industrial Revolution stripped most of those informal breaks away. By the mid-nineteenth century, factory workers in Britain, the United States, and Germany routinely worked 70 to 80 hours across a six-day week, often in unsafe conditions. The campaign for shorter hours became one of the founding causes of the labour movement.

The Half-Saturday Compromise

The first crack in the six-day week was the half-day Saturday, which spread through British factories from the 1840s onward. Workers finished at 1 or 2pm on Saturday, giving them an afternoon to shop, attend sport, or run errands. The half-Saturday was not a religious accommodation — it was a commercial one. Shops needed customers with both money and time, and the Saturday half-day created the modern consumer economy: the FA Cup Final still kicks off at 3pm on a Saturday because that is when working-class crowds first became free to attend.

The Jewish Sabbath and the Origin of the Two-Day Weekend

Saturday off is, in part, a Jewish accommodation. As Jewish workers entered American manufacturing in large numbers in the late nineteenth and early twentieth centuries, the conflict between the Saturday Sabbath and a six-day workweek became unavoidable. Some employers granted Saturday off in exchange for working Sunday; others, recognising the impracticality, gave both days. A New England spinning mill is generally credited with the first true two-day weekend, in 1908, explicitly to allow Jewish employees to keep the Sabbath without losing the Christian Sunday.

Henry Ford and the 1926 Announcement

The five-day, 40-hour week became a national policy when Henry Ford applied it across his entire manufacturing operation in September 1926. Ford's reasoning was famously commercial: workers with leisure time would buy more cars, drive them more often, and create the demand the assembly line was about to flood the market with. He had cut the working day to eight hours in 1914 and doubled wages to five dollars; the 1926 decision completed the bargain. Ford framed it bluntly:

"It is high time to rid ourselves of the notion that leisure for workmen is either lost time or a class privilege."

Ford was not the first — Kellogg's in Battle Creek had been experimenting with shorter weeks since the early 1920s — but Ford's scale forced the rest of the industry to follow.

Statutory Codification: 1938 and the ILO

The five-day week became law in the United States with the Fair Labor Standards Act of 1938, which set a 40-hour standard week and required overtime pay above it. The International Labour Organization had pushed for the same standard with its 1935 Forty-Hour Week Convention, though only a handful of countries ratified it before the war.

By the late 1940s, the five-day, 40-hour week was the default across the industrialised West. France formally moved from 48 to 40 hours in 1936 under the Popular Front government. The UK reached 40 hours by collective bargaining rather than statute, finishing the transition in the 1960s. Japan held out longer — the six-day week persisted in many large companies until the 1980s, when government policy and bank closures pushed Saturdays decisively into the weekend.

Post-WWII Consolidation

The post-war decades cemented the five-day, 40-hour pattern as a global norm:

• The Soviet bloc adopted the five-day week in 1967 after Khrushchev's reforms.
• South Korea moved from a six-day to a five-day week in 2004 for large employers and 2011 for small ones.
• India formalised the five-day week for central-government employees in 1985, though most private firms still expect Saturday work.
• Saudi Arabia shifted its weekend from Thursday–Friday to Friday–Saturday in 2013 to align with international markets.

The Modern Four-Day Experiment

The five-day week is now itself under pressure. Three large recent trials have generated evidence that a four-day week with no pay reduction is feasible for many knowledge-work organisations:

• Iceland (2015–2019). Public-sector trials covering roughly 1% of the workforce reduced hours from 40 to 35–36 with no productivity loss. Today, around 86% of Icelandic workers are on shorter-hours contracts.
• Microsoft Japan (2019). A one-month four-day-week trial reported a 40% productivity uplift and lower electricity use.
• UK pilot (2022). 61 companies and roughly 2,900 employees ran a six-month four-day-week trial; 92% of participating companies opted to continue. Revenue stayed flat or rose; sick days dropped sharply.
• Spain, Belgium, Portugal, and South Africa have since launched government-backed pilots of their own.

What Comes Next

The likely future is not a single rigid week but a menu: 40 hours over four days, 32 hours over four days, compressed schedules, and asynchronous remote work across time zones. Employment law and HR systems will have to keep pace. Notice periods, leave accrual, and "working day" definitions all assume the Monday-to-Friday template — when that template fragments, contracts and calendars will need to evolve with it.

The One-Hundred-Year Arc

From Ford's 1926 announcement to the UK's 2022 four-day pilot is almost exactly a century. In that span, the working week shrank from six days to five and the working year fell by roughly 800 hours per worker. If the next century follows the same trajectory, today's five-day calendar may look as antique as the medieval six-day one does to us.

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