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Thermal Scope Range: Longest IR Optics Zoom

L.p. Brezny | Updated June 1, 2023 | Why You Should Trust Us | How We Earn Money
cover photo of thermal scope range showing the lens of thermal scope, article title, and logo

If you’ve heard of thermal scopes before, you’ll likely know that it’s a great tool to see targets in lowlight scenarios or when visibility is obscured through detecting heat signatures. 

But how far it can see compared to a standard riflescope is the question that needs answering – what exactly are its distance limits?

We’ll be covering all you need to know about thermal scope range and the factors that affect it.

Thermal Scope Long Range

Thermal scopes can be used any time of the day when you need to spot or track heat-emitting targets, and they can be used at quite a range too, depending on the product you choose. too

Now, these scopes are especially effective when you’re in a position that allows you to take long shots, usually considered 400 yards away or more. For these types of long-range shots, a scope that has a bigger focal length in its objective lens is required. 

So, what does that mean?

Well, a bigger focal length means higher magnification and smaller field of view, your magnification gets bigger but the angle of view conversely decreases. You will need at least 50mm to easily see around 1800 to 2000 yards. (1)

A thermal scope with a rangefinder can help you understand exactly how far away a target is and will let you know if the shot is within your abilities. This can be the difference between scaring off the target or hitting it. Some thermal scopes have this feature while others don’t, so a rangefinder is a good choice if you need to definitively know the distance you’re shooting.

Iray Rico LRF seen with rangefinder
A Rangefinder Comes Standard on Many Thermal Scopes

How Far Can Thermal Scopes See?

Well, a thermal scope can have a very long range of vision on them, the average one reaching out past a thousand yards.

How it does that is by combining zoom capabilities and its refresh rate with the range to allow it to better render the target in the scope.

Now, high-quality thermal scopes are often equipped with both digital or optical zoom and retain a high refresh rate. It’s this that gives them a longer range and the ability to detect targets up to 4000 yards. A less expensive thermal scope will allow sight of up to 1000 yards, which is still a great range and as much as many people will ever need.

What Thermal Scope Has the Longest Range?

The highest quality thermal scopes available will have a range of up to about 4000 yards. However, this number doesn’t represent the effective distance; you’ll see the objects in the scope at this range but may not be able to hit them accurately. 

In addition, these types of scopes are also an investment, with the pricing ranging from reasonable to exceedingly expensive. However, many also fall between the two extremes, which gives you, the buyer, many options.

What Thermal Scope Has the Longest Zoom?

The longest zoom in a thermal scope may go up to 40x, with the ATN Thor 4 providing a model with 4-40x magnification. That may sound insane compared to the standard scope with a zoom of 3-15x or 4-16x, but truth is, the zoom required will vary depending on the needs of the shooter. 

These scopes with a higher quality zoom bring shooting to another level but usually come with a higher price point too. 

Now, you might be wondering how magnification actually works in a scope relative to distance, and here are some examples:

For instance, if you want to see 1000 yards as if it were 100 yards away, you’ll need a scope with a magnification of 10x. If you wanted to see 4000 yards as if it were 100 yards away, you would need a zoom of 40x to do so.

However, you should be careful when looking at magnification in thermal scopes because there’s a difference between optical magnification and digital zoom.

Optical magnification enlarges the target without losing image quality, but digital magnification enlarges the image itself that you receive, which can result in a blocky and unclear picture. Most scopes specify the magnification types, so look out for this spec when looking at thermal scopes.

Zoom vs. Effective Range vs. Identification Range

Zoom is how the scope magnifies the object you’re sighting, as we mentioned above. So, with a magnification of 20x, you can see 2000 yards as if it were 100 yards away.

An effective range is not the full range that the scope can see up to (which would be the detection range). Instead, it’s the range you will more or less be guaranteed to hit the target from.

Identification range refers to the range in which someone can positively identify their target. So you may be able to see something through the scope, but if you cannot precisely identify the target, that object is outside of that scope’s identification range.

Factors Affecting Thermal Scope Range

Here are some important elements to consider when it comes to thermal scope range, which can affect the ability, accuracy, and range of the imager:

  • Size and quality of the lens
  • Pixel count in imaging sensor
  • Environmental conditions
  • Battery life
  • Resolution
  • Reticle pattern
  • Magnification type

Ultimately, the quality of the scope will greatly affect your range. Better components bring you better image quality, and for the ranges you may want to reach, that can become essential.

Consider all of these factors and how you want to use your thermal scope before purchasing to get the best fit for your task.

Long Range Thermal Scopes

If you’re looking for thermal scopes that preform well at a distance, make sure to check out our article on the top long range thermal scope options. We cover the optic for every type of hunter at any range.

Thermal Scope and Eye Damage

It is a common question if thermal scopes can cause eye damage. Short answer, no, but there are some consideration you should take if you’re using a thermal optic for extended periods of time. Make sure to read our article on thermal scope and eye damage if you have any similar concerns.


What is the Farthest Effective Range on a Thermal Scope?

The farthest effective range on a thermal scope is about 800 to 1000 yards (730 to 915 meters). This can change depending on the level of skill that the shooter possesses and the firearm they utilize.


  1. Nikon USA, Understanding Focal Length, retrieved from https://www.nikonusa.com/en/learn-and-explore/a/tips-and-techniques/understanding-focal-length.html

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