Watches offer infinite possibilities. Watchmaking, hand in hand with technology, grows exponentially, creating added value to timepieces. Among these technologies are complications, such as the tachymeter, which stands out among the truly special timepieces.

What is the tachymeter used for in a watch?

Hawker Hurricane with tachymeter on the dial

The tachymeter is a numbered instrument which measures the speed at which a vehicle or object is moving at a distance known to the wearer. They can be found printed on the dial or directly on the bezel of the watch.

Tachymeters allow the user to calculate time averages, so a watch with a tachymeter will allow you to know, as long as you have a reference point, the speed or distance at which you travel along a road or carry out a task.

This complication emerged around the 1930s and became popular in the world of aviation and motor racing.

Raymond Weil Freelancer with tachymeter on the bezel

To measure speed with a tachymeter, you need to know the distance travelled before you can activate the chronograph. The chronograph is activated at the start of the trip and slows down at the end of the trip, e.g. 1 kilometre. The hand of the watch will show on the tachymeter scale how fast we are going.

To measure the distance, if you know how fast you are travelling, for example 100 km/h, find 100 on the tachymeter scale, which would be at 36 seconds. You can then activate the chronograph when you pass a reference point, for example a bridge. And so, when the chronograph reaches 36 seconds (100 on the tachymetric scale) it slows it down. You know that you have covered one kilometre there.

How to use the watch tachymeter