What Does 4 12×50 Mean on a Scope?

I spend a significant part of my day job talking about scopes and answering questions about scopes. While some of the questions are unique or different, a great many of those questions are asked repeatedly. I try to make note of the more commonly asked questions, in an effort to put the answer (at least my interpretation of the answer) down on paper.

By far the most common questions I hear in person and am asked via email off this web site are focused on rifle scope magnification and how to read scope numbers. One that I often asked about rifle scope numbers is this one: what does 4 12×50 mean on a scope?

Before I get into the answer, let me provide some basic background information about rifle scopes so my answer makes more sense.

Scope Magnification Explained

First, it’s important to understand the context of scope magnification. Without getting overly technical, rifle scope magnification is measured against what the naked eye sees. So, a scope adjusted to 4 power would magnify to 4 times what the naked eye can see. A scope adjusted to 24 power would magnify 24 times what the naked eye can see.

This magnification against the naked eye assumes a person with a vision of 20/20, and this magnification approach is universal in the scope world. By that, I mean that scopes from every country or geography use the power magnification as compared to the naked eye approach.

Scope Types

Rifle scopes are loosely grouped into two different categories:

• Fixed power scopes
• Adjustable powered scopes (which are also called variable power scopes)

Fixed Powered Scopes

A fixed power scope is a scope that has a fixed or non-adjustable magnification setting. This style was the first rifle optic on the market and was very popular in the 60’s and 70’s as it was the most cost-effective way to put optics on a rifle or shotgun.

I grew up shooting rifles (and shotguns for deer) with fixed power scopes so I’ve got quite a bit of experience with them. Fixed power scopes are generally fairly simple to operate as most don’t have an adjustable objective and most have a fixed parallax.

And when I say simplistic, I mean that they were basically look through the scope and shoot as they did not offer any adjustment of any kind.

Fixed powered scopes featured a magnification that ranged from as low as 2.5x all the way up to a fixed 20x power. The most popular fixed power models were the 4x, 6x, and 8x models.

When adjustable power scopes hit the market and became more affordable, the fixed power scopes started to fall out of popularity.

Variable Power Scopes

Variable power scopes feature a magnification range that can be adjusted from one power to another. The magnification adjustment is done via a power adjustment ring, located on eye piece, that rotates. The eye piece is marked with numbers that corresponds to the power magnification.

Early variable power scope models featured a very low range of magnification, while modern models feature a range of magnification that averages 8 magnifications but can go up as high as 25 magnifications.

Today, variable powered scopes have almost become the industry standard as there are only a few fixed powered scope models that are still being produced.

By far, the most popular variable power scope configuration is the 3x to 9x models as they offer a magnification range that will work for most shooting and hunting needs.

How to Read Scope Numbers

A fixed power scope will have two numbers and look like this: 4×32. The first number is the magnification power and the second number is the size of the objective in millimeters. The objective is located on the end of the scope opposite from the end you look through.

Continuing with the fixed power scope examples:

• If you see a scope marked as 6×40, then it’s a fixed power scope with a 6x power magnification and a 40mm objective.

• If you see a scope marked as 8×42, then it’s a fixed power scope with an 8x magnification and a 42mm objective.

Variable power scopes feature 3 numbers that read slightly different from the numbers on a fixed power scope. With a variable power scope, the first two numbers indicate the range of the magnification and the 3rd number is the size of the objective in millimeters.

The numbers on a variable power scope will look more like this: 3-9×40. In that example, the scope is a variable magnification model with a magnification range that starts at 3x and goes all the way up to 9x and features a 40 mm objective.

With variable powered scopes, the first number listed on the scope is always the lowest number in the magnification range while the second number is always the highest number in the magnification range.

Continuing with some variable power scope examples:

• If you see a scope marked as a 4-16×44, then it’s a variable powered scope with a magnification range that starts at 4x and will adjust all the way up to 16x, with a 44mm objective.

• If you see a scope marked as a 6-20×50 model, then it’s a variable powered scope with a magnification range that starts at 6x and will adjust all the way up to 20x, with a 50mm objective.

Here’s a real-life example of a scope box with all the numbers on the box so you can get a better idea of what I’m talking about:

The example box here is from a Sightron S-STAC scope. In the box above, you can see the “S-TAC 4-20X50 MOA” displayed. In that example, the 4-20 numbers mean that the scope is a variable powered model with a magnification range that starts at 4 power and adjusts all the way up to 20 power. The x50 portion means that the scope has an objective that is 50mm in diameter.

Now, lets go back to the original question that was asked at the beginning of this article: what does 4 12×50 mean on a scope?

The 4 to 12 marking mean that the scope is a variable powered scope. Normally the magnification range is marked with 2 numbers separated by a dash, but in this case the dash was left off. So, the 4 to 12 means that the scope has a magnification range that starts at 4x and adjusts all the way up to 12x. The 3rd number, which is 50, means that the scope has a 50mm objective.

Once you understand the format of rifle scope numbers, you can decipher the numbers for any rifle scope.

FAQS

Here are some other frequently asked questions that I see and hear regarding rifle scope numbers:

How do I tell what power a scope is if it doesn’t come with the original box?

Ah a good question. To determine the magnification range, look at the marking on the magnification ring. The lowest number on the ring will be the first number in the format and the largest number marked on the ring will be the second number in the format.

The objective is usually marked in millimeters somewhere either outside or inside the objective. If it’s not, you’ll have to either measure the circumference of the objective and then convert that number to millimeters, or just estimate the size.

When I say estimate the size, I’m talking about comparing the size of the unknown objective up against the size of a known objective. Objectives usually some in common sizes such as:

• 32mm
• 38mm
• 40mm
• 44mm
• 50mm

By comparing a known objective to the unknown, you can narrow down the approximate objective size.

Exactly what does 4×32 scope mean?

A 4×32 scope is a fixed powered scope (as in the magnification is fixed at 4 power) with a 32mm objective. The objective is the end of the scope opposite from the end you look through.

The 4×32 configuration is probably the most popular fixed power scope configuration ever invented. When I was a kid and first got into shooting, a fixed 4×32 scope was really one of the only scope options on the market if you didn’t want to spend a fortune.

What does 4 16×50 mean on a scope because it doesn’t have the dash that I usually see?

Even though those numbers don’t have the dash that you normally see that configuration is still is variable powered scope with a magnification that starts at 4x and adjust all the way up to 16x. The final number of 50 means that the objective on the scope is 50mm in size.

In regards to the dash that you normally see between the first and second numbers of the magnification range: not every rifle scope brand uses a dash in between those two numbers, so it’s important to understand that with or without the dash, scope numbers in that specific format mean the same thing.

What does 6 24×50 mean on a scope?

With these rifle scope numbers, this is a variable powered scope with 6x as the lowest magnification setting. The magnification range starts at 6x (as in 6 times what the naked eye sees) and can adjust all the way up to 24x (as in 24 times what the naked eye can see). The last number in the series, which is 50, means that the scope objective is 50mm.

A scope like this is also commonly listed as a 6-24×50 model as well.

On a 3 9×50 scope, what do the numbers mean?

The 3 9×50 numbers mean that the scope is variable power model with a power magnification range that starts at 3x and can adjust all the way up to 9x. The last number in the series, which is 50, means that the scope has an objective that is 50mm around. The numbers on this scope are also commonly listed or shown as 3-9×50 as well, so don’t let the lack of a dash in the numbers confuse you.

The 3-9 magnification is still one of the most popular magnification ranges that are sold today, and super popular for deer hunting.

What do the numbers on a rifle scope represent?

The first two numbers associated with a rifle scope represent the power magnification range, and the last number in the series represents the diameter of the scope objective. Normally, these numbers are listed in a series of 3 numbers with the first two being separated by a dash and the last number being proceeded by an x.

For example, 5-15×44, would be a variable powered scope with a power magnification range that starts at 5x and can adjust all the way up to 15x, with an objective that has a diameter of 44mm.

If I’m looking at a scope and it only has two numbers, what does that mean?

If you’re looking at a rifle scope and it only has two numbers listed on the box, like 8×40, or something along those lines, then you’re probably looking at a fixed power scope.

As the magnification is fixed, there’s only one number listed in the magnification section, which is why that scope is only showing two numbers versus the typically 3 number format you see on variable power rifle scopes.

If I purchase a variable powered scope that goes from 6-20, do I have to use the 20 power as that’s way more power than I need?

With a variable powered scope, the shooter chooses the power magnification setting that he or she wants to use.

So, to answer your question, no you would not ever have to use the 20 power unless you decided that you wanted to.

I know plenty of shooters who like to have a variable powered scope with a higher magnification range (say above 14 power), even though they end up taking most shots on a lower magnification power. Heck, I’m one of those shooters.

I’d much rather have the higher magnification range available if I needed versus not having it.

As I come across more questions related to this topic, I’ll update this page.