Have you ever wondered, how on earth do they calculate the speed of the balls bowled by a bowler in cricket. No, they don’t touch the bowl while it’s being bowler, they don’t even have any speed censors under the pitch.


Then what kind of technology are they using to give us the right figures or they are just spamming us. Well, the latter one is not true, they do tell us the correct speed of the delivery bowled by the bowler and to tell that they use the following method:

Yes, there’s some Physics involved in this but I will try to make the concept clear to you in general terms.

Radar Speed Guns!

A name which most of you have heard about but today we’ll tell you how it works. A radar speed gun (also radar gun and speed gun) is a device that is used to measure the speed of moving objects. You might not have seen this in India but in foreign countries, the traffic police use it to check if a vehicle is crossing the speed limit.

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These are even set up at the red lights to automatically track and spot the limit crossing vehicles. And yes, this is often used in professional spectator sport, for things such as the measurement of bowling speeds in cricket, the speed of pitched baseballs, athletes and tennis serves.

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Where is it placed?

A speed-gun is placed right next to the sightscreen. What’s a sight screen, see below:


It’s placed at such angle that it doesn’t observe any blockage and focuses just on the ball and its speed.

How does it work?

The speed gun measures the speed of the objects at which it is pointed by detecting a change in frequency of the returned radar signal caused by the Doppler effect. In simple terms, this gun has two main components a receiver and a transmitter.

It sends a radio wave and the wave is reflected by any object that comes in its path. In a cricket match’s case, it’s a cricket ball. The gun gets this echo and then by using the principle of Doppler Shift, it calculates the speed of the ball.

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For an in-depth analysis of Doppler Shift, watch the video below:

What’s the standard speed?

However, there has been some problem in everyone’s mind relating the actual speed of the ball. Becuase, we all know a moving object changes velocity or speed and one might ask which is the speed displayed on the screen when we are watching the match?

To solve this issue, the broadcasters have set a fixed distance that is to be traveled by every ball and the time taken for the ball to travel that fixed distance is kept the standard for the calculation of speeds.

First Used in
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This technology was originally used for Lawn Tennis, to measure speeds of Services made by players. Then it was implemented in Cricket.

The speed varies on these factors

The speed, however, can vary due to some factors like weather conditions, air-speeds, etc and even different venues can make changes in the average bowling speeds of a bowler.

Another lesser known fact here is that when the ball reaches the batsman, its speed decreases. Supposedly, if a bowler has bowled around 155 kph, it’s possible that the ball’s speed may decreases up to 110 kph when the batsman plays the shot.

Here a rule applies, Greater the speed with which the ball is released, greater is it decreases in speed.

Speed Guns are pretty accurate but its non-alignment with the ball’s direction can lead to some erroneous results. But, it won’t matter much as they just want to compare two independent cases.

Old Method

Initially, the speed of a delivery was measured using the very common Distance/Time formula, yes we all have read it in Physics.

Ball Coach Radar

The average speed of the ball was calculated by calculating the time it takes to reach the batsman after it leaves the bowler’s hand divided from the Distance between them.

However, it didn’t give accurate results and the broadcasters shifted to a more advanced technology of Radar Gun.