OpticsMag is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Read more.

How Does a Laser Rangefinder Work?

Last Updated:

What do hunters, archers, and golfers all have in common? Rangefinders. These handheld laser devices are essential for calculating distance with ease. Whether you’re shooting an arrow or putting across a green, knowing the distance between you and your target can change the way you aim, the strength behind your draw or swing, and the likelihood of your success. But how do these high-tech gadgets measure distance? Understanding how they work can not only help you choose the perfect model, but it can help you get the most out of using them.

It’s All About the Lasers

A laser is a concentrated beam of light. The energy amplification process used to create a laser means they are packed with energy. They can be used for cutting, surgery, precision measuring, and data-gathering. They’re also the most important component in a rangefinder. When you push the button on a rangefinder, an infrared laser shoots toward your target and rebounds back to the device instantaneously. The rangefinder then measures the microseconds it took for the laser to rebound and return, then automatically calculates the object’s distance for you.

What is Beam Divergence?

This is the quality of focus you get from your rangefinder’s laser. If you think about the way a flashlight beam spreads as it gets farther from the flashlight, you’ll get the idea behind beam divergence. As a laser’s light spreads, it starts reacting to more objects. If you’re trying to focus on a target, you don’t want your beam to diverge much. Of course, if you’re targeting a large animal at close range, this is probably not a big deal. But if you’re squirrel hunting in the sequoias, you’ll want that beam to be precise. As a bonus, the tighter the beam, the better the distance you can range.

What the Rangefinder Sees

When you push the button and send the laser out toward your target, you’re actually sending a series of lasers that are bouncing off everything within the beam’s scope. This happens instantly, providing you with a distance reading before you can blink. While some rangefinders only calculate the distance to the closest object, others will interpret the greatest spike of readings as your target. Some devices will only target the closest object, others will target only the farthest, and some have built-in features that will ignore any brush between you and your target. Every model interprets the data a little differently according to its programming, so if you’re in the market, consider what you’ll be scoping so you can find the right fit.

A Different Angle

Without getting too deep into geometry, elevation of a target can play a role in the rangefinder’s calculations. The difference between the distance downhill to the base of a tree versus the distance straight across to the top of the tree requires some math. You still with me? Don’t worry, some rangefinders are built to calculate angles for you. This can be especially helpful for golfers, as the distance downslope between you and the green can impact how you want to swing.

 SEE ALSO: our comparison of rangefinder binoculars here.

Putting It All Together

All this technology combined creates a device that will take the guesswork out of targeting. No matter your sport or objectives, relying on lasers and digital technology to help you determine distance is sure to enhance your experience. If you get the chance, give one a try so you can get the feel for it. Then you’ll be ready to find the right fit for your needs.

We also recently released an article on the different use-cases for a laser rangefinder. Find that article here.