Everyday mysteries solved: Why do clocks run clockwise and not anti-clockwise? The surprising reason goes back 5,000 years

Most of us check the time several times a day without giving a second thought to how a clock actually works. One thing that almost never gets questioned is the direction of the hands. Whether it is a wall clock, wristwatch or a clock tower, the hands move clockwise. It feels so natural that the opposite seems strange. But this wasn't decided by any law of science. The reason goes back thousands of years and starts with one of humanity's earliest timekeeping tools, the sundial.

Long before mechanical clocks were invented, people used sundials to measure time. Historians believe the earliest true sundials appeared in ancient Egypt around 3,500 years to 5,500 ago, though some prehistoric monuments are also believed to have been used to track the Sun.

A sundial works using a fixed pointer, known as a gnomon, that casts a shadow on a marked surface. In the Northern Hemisphere, the Sun appears to move from east to west across the southern sky. As the Sun changes position through the day, the shadow moves from west to north and then to the east. This creates the same circular movement that we now recognise as clockwise.


Because this pattern was familiar for centuries, it became the natural model for later timekeeping devices.

How mechanical clocks copied the Sun

Mechanical clocks arrived much later. The earliest mechanical timekeeping device is believed to have been developed in China around 725 CE. Gear-driven clocks later appeared in Europe between northern Italy and southern Germany during the late 13th century.

Early European clocks did not always have hands. Many simply struck bells to mark the passing hours. But once clock hands became common, clockmakers designed them to move in the same direction as the shadow on a sundial. There was no technical reason they had to move that way. It was simply what people already understood.

Since mechanical clockmaking developed in the Northern Hemisphere, the clockwise direction became the accepted standard and eventually spread across the world.

Could clocks have moved the other way?

Interestingly, the answer is yes.

In the Southern Hemisphere, sundial shadows move in the opposite direction. If the first major clockmaking traditions had developed there instead, today's clocks might have run anti-clockwise.

This idea even inspired a modern example. In 2014, Bolivia installed an anti-clockwise clock on its Congress building in La Paz. Explaining the decision, Bolivia's foreign minister David Choquehuanca told The Guardian: "We're in the south and, as we're trying to recover our identity, the Bolivian government is also recovering its sarawi, which means 'way' in Aymara. In keeping with our sarawi – or Nan, in Quechua – our clocks should turn to the left."

Counterclockwise clocks do exist

Although uncommon, anti-clockwise clocks are not entirely new. One famous example is the historic clock inside the Duomo in Florence, created by Paolo Uccello. Another can be found on Prague's Jewish Town Hall, where a clock with Hebrew letters runs counterclockwise.

Rabbi Harlan J. Wechsler explained the tradition by saying: "Going counterclockwise is not entirely strange to Jews. Did you ever notice, for example, that when the Torah is marched around the synagogue, we march it counterclockwise to the ark which is, theoretically, at twelve o'clock? That custom comes from the procedures of the priests in the Temple who walked up the slanted front of the altar and then would proceed counterclockwise around its periphery performing their required functions."

A tradition that has lasted for centuries

Today, digital clocks have reduced our dependence on moving hands, but the clockwise direction remains unchanged. What feels like the most natural way to read time is actually the result of geography, astronomy and centuries of tradition.

The next time you look at an analogue clock, remember that its movement is following a path first traced by the shadow of the Sun thousands of years ago. What seems like an ordinary detail today is, in fact, a small piece of history that has survived for generations.