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Home Tool Bag Advice How Does a Laser Measure Distance?

How Does a Laser Measure Distance?

A laser measure is a fantastic and important tool for people who work in the real estate industry and construction. It can make measuring an area an absolute breeze. It requires virtually no effort and can be done single-handedly.

Since they are so easy to use, both professionals and amateurs are able to use them. Now we are all aware of the fantastic benefits laser measures have but have you ever wondered how does a laser measure distance?

We are certain that not many of you know the answer to this. So, for the curious folks out there, we decided to dig deep and talk about the science behind this amazing power tool. First, let us briefly tell you what exactly a laser measurer is.

What Is a Laser Measurer?

A laser measure, also popularly known as laser distance meters, is basically a new-age alternative to regular tape measures we used to use back in the day. All the measurements are taken through the device via a pulse of light coming out of it and hitting the defined target. This then measures the time that is taken for the reflection to return.

Laser measures offer highly accurate results even with large distances. Most laser measures come with some interesting features, such as the ability to add, subtract, and calculate volume and area, triangulate, and many more functions.

With so many functions, it is obvious that it brings a whole lot of benefits on the table for the user. It can figure complex, time-consuming calculations far easily and quickly, but most important of all, with higher degrees of accuracy.

Do note that to get the most accurate results from a laser measure, you must select a high-quality one from a reputed brand. Laser measures are great for professionals such as contractors, builders, tilers, architects, surveyors, floor contractors, kitchen fitters, and more.

How Does a Laser Measure Distance?

Now that you have a basic understanding of what a laser measure is, it is time we discuss about the way a laser measures distance.

Operating Principle

As mentioned earlier, a laser measure shoots a beam of the laser at the target. This pulse will then reflect off of the target back at the measuring tool.

The principle of the “time of flight” is on the fact that the laser pulse will travel at sort of a consistent speed through the planet’s atmosphere. Inside the measurer, there is a simple computer that will quickly calculate the distance to the target.

This method of calculating the target is also capable of measuring the distance of the moon and Earth within just a couple of centimeters. You can also find laser distance measurers being called as a laser range finder or just range finders.

Calculating the Distance

The distance between the target and the device itself is written as D=ct/2. Here, c refers to the speed of light, and t refers to the time that is taken for a round trip between the target and the measurer.

With the laser pulse’s high-speed traveling and its focus, there is a rough calculation that is very accurate over the distances of miles or feet. However, this loses accuracy over much farther or closer distances.

Why Are Lasers Used?

One of the main reasons why lasers are used is because they are a focused and intense beam of light, which typically has a frequency that is single. They tend to be quite useful when it comes to the measurement of distances.

Lasers travel at a fairly constant rate through the atmosphere and travel for long distances before the divergence, which is the weakening and spreading out of the laser beam. All of this reduces the efficacy of the measurer.

Furthermore, unlike white light, which disperses easily, laser light does not tend to do so. This means that the laser light can travel a much greater distance without losing its intensity.

In comparison with ordinary white light, a laser beam will retain much of the original intensity when it is reflected off of the target. This is crucial when it comes to calculating the distance to an object.

The Receiving Optics

To ensure that there is reliability, the laser distance measurer employs some methods to minimize the light in the background.

When there is too much light in the background, it can potentially affect the measurement as the sensor could mistake some of the bright background light for the reflected laser beam. If this does happen, you will definitely get a false distance reading.

To give an example, when a laser distance measurer is used in areas such as the Antarctic, wherein the background light is immensely bright, it will employ a combination of split beam frequencies, narrow bandwidth filters, and a very small iris to block as much of the interference from the bright background light as possible.

Multiple Applications

Laser distance measurers and range finders are known to have a large variety of uses. These include uses in the field of sports and even when making maps. These tools are helpful in creating maps on the floor of the ocean or even topography maps cleared of vegetations.

Laser distance measures are used actively in the military too. They can provide the exact distance to the targets for the artillery or the snipers, for engineering, and for reconnaissance. Designers and engineers are also known to use laser distance measurers in that they help in constructing 3D models of certain objects.

Lastly, you will find several hunters, archers, and golfers these days all employing range finders so that they can calculate their exact distance to their respective target.


Thanks to this article, you now know how does a laser measure distance. There is quite a bit of science and mathematics involved in this whole process.

To sum it all up and to keep it simple, the laser from the laser measurer sends out a pulse which hits the target you are aiming at and then lets the pulse return back to the measurer. The measurer then measures this distance and voila! The results are highly accurate measurement readings.


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