How Many Cubic Feet Is My Gun Safe? Everything About Size Gun Safe

How Many Cubic Feet Is My Gun Safe? Everything About Size Gun Safe
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Many valuable items need secure and generous storage in your house: deeds, jewelry, titles, electronic media (drivers, photos), and insurance papers. A gun safe is an excellent container for them, aside from ammo and firearms. You must have at least once wondered, “how many cubic feet is my gun safe?” 

Gun safes are available in various sizes (estimated in cubic feet). Therefore, a cubic foot can store a long gun. If we rely on that rule, a 20-cubic-foot gun safe should hold 20 long guns.

Let’s head to more interesting info below!

How Many Cubic Feet Is My Gun Safe?

To determine the cubic feet of your gun safe, you’ll need to measure its internal dimensions. Most gun safes provide these dimensions in the owner’s manual or on a label inside the safe. Typically, gun safe dimensions are measured in inches.

Once you have the measurements of the length (L), width (W), and height (H) of the interior of your gun safe, you can calculate the cubic feet using the following formula:

Cubic Feet = L x W x H / 1728

Make sure to convert all measurements to inches before using this formula. The division by 1728 is necessary because there are 1,728 cubic inches in 1 cubic foot.

For example, if your gun safe measures 60 inches in height (H), 30 inches in width (W), and 24 inches in depth (L), the calculation would be:

Cubic Feet = 60 x 30 x 24 / 1728 = 180,000 / 1728 ≈ 104.17 cubic feet

So, your gun safe would be approximately 104.17 cubic feet in size based on these measurements.

Liberty Gun cabinet

Do I need a large gun safe?

We usually have some specific valuables to keep and a specific storage space to utilize.

A basic thumb rule for safe gun measurement is that one long gun will fit into a one-cubic-foot safe. So, if your gun safe can hold 25 long guns and other small items, it is 25 cubic feet.

However, reality seems to be a bit different. With scopes and bolt actions, capacity is somewhat less than what we expect.

The size of your safe directly affects its weight, cost, and storage capacity. Knowing the size well will help you have a good measurement of both weight and capacity.

Also, for those planning to buy a gun safe, you don’t wish to splurge tons of money to go home with something that doesn’t have enough space to fit your stuff collection.

Even if you just intend to put in the smallest item in the future or want to store lightweight properties, like jewelry, antiques, personal documents, or money, it’s advisable to go for bigger safes than your needs.

Though manufacturers have offered the detailed dimensions of the products, most gun safes come with sizes represented as a measure of the number of guns the user can store in them. So, it’s common to see a safe advertisement that says: A 12-gun safe or 16-gun safe.

Old-fashioned wood stock firearms seem smaller, enabling retailers to advertise more spacious gun storage that is not large enough to store modern weapons.

Modern hunting kits will surely take up more room than traditional ones in a safe, concerning attached optical gadgets, extended magazines, or pistol grips.

According to a general thumb rule, if your item collection includes many modern pieces, size down the gun capacity advertised by half to determine if that safe is right for you.

We’ve never encountered someone regretting purchasing a safe to keep their firearm and ammo collection secure. But we did encounter many people regretting not buying a bigger gun sage.

Why? Since their gun collections will continue to grow while the safe size will not increase. The same also goes for their essential documents and valuables.

Read: Sizes of Gun Safes

Buying a gun safe can help you protect your properties from damage like collisions or fire and theft. Yet, it can do the job effectively only when the size is significant enough to store them.

This video shows you how to choose the right size gun safe:

How Does Size Affect the Cost of A Safe?

Larger capacity safes generally cost more, whereas smaller safes cost less, depending on their features and specs.

Most producers make it straightforward to level up to a more spacious safe with pricing. A big safe with twice larger capacity as a smaller one won’t be double in price.

Typically, you will look at the difference between $300 and $500, meaning that it’ll be way cheaper to buy a 40-gun safe than two 20-cubic-foot safes.

Best Gun Safes Under $300

Best Gun Safes Under $500

Thus, when shopping, remember that you are not just shopping for the present. You need to buy something that can go with you over the long term.

What Size Of Dehumidifier Do I Need For My Gun Safe?

How Long Do Gun Safe Dehumidifiers Last

The size of the dehumidifier depends on your safe’s size.

Adsorption dehumidifiers or desiccant dehumidifiers are containers full of hydrophilic materials appearing like silica gel.

These devices are a fantastic option for safe owners who aren’t into using electricity or drilling holes in their safes’ walls.

When buying a desiccant dehumidifier, you have to match the size gun safe with capacity. Big-sized safes will require a big-sized dehumidifier and vice versa.

Dehumidifiers for gun safes come in various levels of durability and capacity. Most larger models cover around 333 cubic feet.

Check: Best Gun Safe Dehumidifier

If the moisture in your safe is not high and you just want to maintain the safe, desiccant dehumidifiers are the way to go.


1. How many cubic feet are in the average gun safe?

  • The average gun safe typically ranges from 8 to 40 cubic feet, depending on the size and capacity. It’s essential to measure the interior dimensions of your specific safe to determine its cubic footage accurately.

2. How many cubic feet is a 30 gun safe?

  • A 30-gun safe can vary in size, but it typically falls in the range of 12 to 20 cubic feet. Be sure to check the manufacturer’s specifications for the exact measurements.

3. How many cubic feet is a 36 gun safe?

  • A 36-gun safe usually has an interior space ranging from 15 to 25 cubic feet. Always refer to the manufacturer’s information for precise measurements.

4. Do I need a dehumidifier in my gun safe?

  • Yes, it’s highly recommended to use a dehumidifier in your gun safe. Maintaining the proper humidity level inside the safe helps prevent rust and corrosion on firearms and other valuables.

5. How big is a 1.2 cubic foot safe?

  • A 1.2 cubic foot safe typically measures around 16 inches in height, 14 inches in width, and 12 inches in depth. Please check the specific product details for accuracy.

6. How big is a 1.5 cubic foot safe?

  • A 1.5 cubic foot safe generally has dimensions of approximately 18 inches in height, 16 inches in width, and 14 inches in depth. Always confirm with the manufacturer’s specifications.

7. How many cubic feet is a 40 gun safe?

  • A 40-gun safe typically offers an interior space ranging from 20 to 30 cubic feet. The exact dimensions can vary depending on the model and manufacturer.

8. How many cubic feet is a 64 gun safe?

  • A 64-gun safe can have an interior space of approximately 30 to 40 cubic feet. To get the precise measurements, refer to the manufacturer’s product information.

9. How big is a 40 gun safe?

  • The size of a 40-gun safe can vary, but it usually measures around 60 inches in height, 30 inches in width, and 24 inches in depth. Always check the product specifications for accuracy.


Like refrigerators, safe gun producers used to estimate size in cubic feet. However, as gun safes have become more popular and appeared in many retail shops, the measurement of cubic feet turns confusing to customers.

This post not only answers the question “how many cubic feet is my gun safe” but also clues you into some tips when choosing a gun safe.

We hope you find this new knowledge helpful.

Thank you for reading!

Lisa J Thompson
Lisa J Thompson

Hello, my name is Lisa Thompson and I’m the Founder of Safety Hub, your go-to resource for all things home improvement. In this day and age, security should be your top priority, and that’s exactly why my dedicated team of writers and I offer reliable information pertaining to gun storage, home safes, and so much more. When I’m not running the blog, I enjoy gardening and homesteading. As an avid nature lover, I also love going on camping trips. Currently, I happily reside in the heart of Los Angeles.

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