Cubic Inches to Liters Backpack: 5 Standard Sizes Everyone Should Know About (2024)

Last updated on August 23rd, 2022 at 07:45 am

Cubic Inches to Liters Backpack: 5 Standard Sizes Everyone Should Know About (1)

Backpacking has become a popular way for people to travel. It is often cheaper than staying in hotels, and it can be an adventure all on its own. However, some people may not know what size backpack they need before heading out for their trip.

Knowing the difference between cubic inches and liters will help you understand what size of pack you should get depending on how long your trip is going to be. Cubic inches are used more frequently in the United States while liters are used more commonly outside of the US, so knowing both measurements will ensure that you have enough space for everything that you want to bring on your trip.

This cubic inches to liters backpack size guide will give you all of the information you need to know about both units so that you can decide which size is best for your needs!

Table of Contents

Methods of Measuring Backpack Size

When purchasing a backpack, it is important to consider the dimensions and volume of the bag. There are many ways to measure these aspects of a backpack. You can use your hand as a measuring tool or you can look at specific measurements on the product page before buying one. The most accurate way to determine if your items will fit in a backpack is by using its actual dimensions and volume.

Measuring Actual Dimensions

You can find out the actual dimensions of a backpack by using a ruler or measuring tape to measure the following dimensions:

Width measured at the widest point of the backpack. This is typically where your shoulder straps are attached. Some companies may show a backpack’s width on its product page, but if that information isn’t available or you can’t find it then simply measure this yourself using a tape measure or ruler.

Height measured from floor to top of the bag. Measure from the bottom of the bag and add 2 inches for room to pack the bag full.

Depth measured from the back of the backpack to the front. Most companies will note the depth on their website however if they don’t list it you can use a ruler to get an accurate measurement through trial and error once you have a physical copy of your target backpack in your hands.

Measuring Volume

A good way to measure a backpack is by its volume. When you see an indication such as 35L, this rating refers to the total available room within your bag for all of those things that need storage space!

The number of useful compartments in a backpack is what dictates its volume. Sometimes this includes exterior pockets, like mesh pouches for water bottles; however, it’s not always the case that all these spaces count toward your total bag capacity when measuring up so make sure you know which ones do before calculating how much material will fit inside!

The easiest way to measure a bag’s volume is by multiplying its actual dimensions together to find out a rough estimate of its cubic capacity in liters.

Cubic Inches to Liters Backpack Size Comparison

Cubic Inches to Liters Backpack: 5 Standard Sizes Everyone Should Know About (2)

Cubic inches and liters are measurements of volume, which means they both measure how much space an object takes up. This section will explain what cubic inches and liters are and how to convert from one to the other.

Cubic Inches vs Liters

A backpack can be measured in both cubic inches and liters. Which is correct?

Cubic inches (CI) are the old way of measuring pack volume (how big it is). A cubic inch is 1in x 1in x 1in, so if you take the width, length, and height it will give you a measurement in CI. The reason this came about was that back in the 1930s packs were not as big as they are today. 1,000 CI is a pretty small pack, and 2,200-2,300 CI would be a medium-size pack (a very good first ‘starter’ pack for people).

Liters (L) are a newer way of measuring the volume of packs. A liter is not quite 1 gallon; it is close to 0.9 gallons (to be exact, there are 3.79 liters in one gallon). 2,300CI is equivalent to about 38 liters and so on.

You will see both CI and L measurements on most gear sites these days. You will often see a combination of both when talking about packs, but usually, it is about the volume of the pack. A good conversion for CI versus L is that 1,000CI = 16.4L and so on.

Cubic inches are still widely used in the outdoor community, but liters are gaining traction. Many gear companies list both measurements out of tradition. For example, you can buy a 65 liters pack or a 3966 cubic inches pack. Either way, they refer to the same thing–the size/volume of the backpack itself. The numbers may be different but you are looking at basically the same product!

Some Standard Backpack Sizes

The size of a backpack is an important factor to consider when choosing one. The best way to make sure you are getting the right bag for your needs is to know what backpack sizes there are and how they translate into real-world measurements.

Listed below are some standard backpack sizes along with their corresponding volume measurements in liters (L) and cubic inches for each size. This may help you find something that fits your needs perfectly!

BackpackLitersCubic Inches
XS or Kids10 – 20610 – 1200
Small30 – 401800 – 2441
Medium50 – 603051 – 3661
Large65 – 803967 – 4882
XL85 – 905187 – 5492

Common Backpack Sizes

There are two main sorts of backpacks, which are classified by their purposes. These are the day pack and the expedition pack. The difference between them is that day packs are more everyday bags that are used for carrying smaller loads. Expedition packs are designed for more extreme situations where you need to carry more food and equipment with you.

BackpackLitersCubic Inches
Day PacksUnder 402500
Weekend Packs40 – 652500 – 4000
Weeklong Packs65 – 954000 – 6000
Expedition Packs95 and above6000 and above

Why is Backpack Size Important?

Backpack size is an important factor in determining the best fit for your body. While it may be tempting to grab the biggest backpack you can find, this might not always be the best option. Before you go shopping for a new pack, think about how you will use it and what size is truly right for you.

If you are planning on using your pack for day hikes or short overnight trips, there are plenty of options with smaller capacities that are still comfortable enough to carry all of your gear.

Also Read: Where Should a Backpack Sit on Your Back

Choosing the Best Backpack Size: Things to Consider

When you are searching for the perfect backpack, it is important to consider your personal needs. Is comfort more important than space? Do you want several pockets or just one big compartment? What do you need to carry in your bag every day? All of these factors will influence what size bag will work best for you.

The best backpack size for you is the one that will fit all of your belongings and does not weigh too much. The length of your torso, weight distribution, and what you carry are all factors to take into consideration when purchasing a backpack.


Backpack size is a very important factor when deciding which pack to buy. To make the right choice, you need to take into account your trip’s length and activities as well as the maximum load you will carry during your journey.

With this Cubic Inches to Liters Backpack Size Guide, you will be able to find the pack that is perfect for your needs.

We hope that you’ve found it helpful and we look forward to helping you with any of your future backpacking needs.

Frequently Asked Questions

How do you calculate backpack Litres?

The volume of a backpack is usually given in litres. To calculate the volume of a backpack in litres, you will need to know the dimensions of the backpack (in inches), and then convert those dimensions to litres.
For example, let’s say you have a backpack that is 18 inches wide, 16 inches tall, and 6 inches deep. To calculate the volume of this backpack in litres, you would need to multiply the width by the height by the depth, and then convert those inches to litres.
The formula would look like this:
18 inches x 16 inches x 6 inches = 1,728 cubic inches (CI)
1000CI = 16.4 liters
1728/1000×16.4 = 28.3liters
So in this example, the backpack would have a volume of 28.3 litres.

How many Litres is a standard backpack?

A standard backpack typically holds around 20-30 litres, although there is some variation depending on the size and design of the backpack. Some larger backpacks can hold up to 50 litres or more, while smaller backpacks may only hold 10-15 litres.

How many liters fit in a cubic inch?

A cubic inch is a unit of volume that is equal to the space occupied by a cube with sides that are one inch long. One cubic inch is equal to about 16.4 mL, or about one-sixth of a fluid ounce. So if you were to ask how many liters fit in a cubic inch, the answer would be about 0.0164 liters.

Why is a backpack capacity in liters?

The capacity of a backpack is typically measured in liters. But why? Why not use some other unit of measurement, like gallons or cubic feet?
It turns out that liters are actually a quite convenient unit of measurement for backpacks. A liter is a unit of volume that is about the size of a quart (or liter) bottle of water. This is a convenient size for backpackers, as it is easy to estimate how much water they will need for a hike. Additionally, liters are a metric unit of measurement, which is the standard system of measurement used in the majority of the world.
So there you have it! The next time you’re packing your backpack for a hike, remember that the capacity is measured in liters because it is a convenient and standard unit of measurement.

Why do they measure backpacks in liters?

One common unit of measurement for backpacks is the liter. But why liters? And how does this unit of measurement help us when choosing the right backpack for our needs?
The liter is actually a very convenient unit of measurement for backpacks. Backpacks are often filled with irregularly shaped items, making it difficult to estimate the volume in cubic inches or centimeters. A liter is a unit of measurement that is closely related to the cubic meter, making it easier to estimate the volume of a backpack. Additionally, the liter is a metric unit of measurement, which is the standard unit of measurement in the world today.
So, when you’re looking at the size of a backpack, be sure to check the liter capacity. This will give you a more accurate idea of the backpack’s size and how much it can hold.

Cubic Inches to Liters Backpack: 5 Standard Sizes Everyone Should Know About (2024)
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