How To Measure Backpack Dimensions?

Last Updated on May 20, 2021

backpackHas it ever occurred to you that you bought a backpack, and it is too small for the purpose?

Well, believe us, it is not a rare phenomenon, and we have the perfect solution right here in our article!

In here, you shall find everything there is to know about how to measure backpack dimensions.

By learning that, you’ll be able to avoid future mistakes and make sure you are getting the right backpack for you.

Methods of Measuring Backpack Size

So, to find out if your backpack is fit for a hike or a trip, it is essential to know its dimensions.

And, with the help of our article, that task is made so much less complicated.

You shall find a thorough walk through on all the utensils you will need for the job, the methods you can use to do the task, and various other helpful information.

So, let’s learn how to measure the backpack dimension.

Tape Measure

Well, your impulsive response to measuring the actual lengths of the backpack might be to use a ruler.

Now, it is true that you will be able to measure the dimensions of the backpack using the ruler, but face it, backpacks tend to be way larger than an uncomplicated ruler can scale.

Besides, the ruler (plastic, steel, or anything) are hard structures. When you are attempting to use these solid items on an object like a backpack, then it can be quite tricky for you to take accurate to measure backpack

So, what is the answer? We use a tape measure! These are much larger in size, have a more accurate spacing between the gratings, and are not rigid at all.

Thus, using them will provide you with the most promising results and will enable you to have a better idea of how much space does the item provides you.


With every backpack, there is a rating called liters, which is a representation of the three-dimensional size of the item. And you can use this to determine the space that contraption is going to provide you. Plus, to calculate the area from the volume, you just need a calculator.

And another great thing about using this is that when you are using this, you are including the pockets from the equation and various other exterior features that your backpack has to offer. And this is a more accurate way of measuring the dimensions of the backpack.

So, if you are wondering how you can do so, there is a simple equation that you will be using to do that task. Remember your eighth-grade math skills? We bet that you never thought that would come in handy. Yeah, that is pretty much all you require to find the dimensions from this.

How to Measure Using These Methods?

Now that you know the methods of measuring, it is time that we understand the fundamentals of how to use these methods to determine the dimensions of the product. And we assure you, if you follow these steps, that task will become quite an effortless task.

Using Measuring Tape

Working with measuring tape is quite an effortless task, and if you want the ideal measurements, then all you have to do is follow these simple measurements!

  • Step-1 (Deciding Which Utensil to Choose)

The first step of measuring the dimensions of your backpack is picking types of equipment that you are going to use. And, as we have suggested before, you could either choose a measuring tape or a ruler.

But we emphasized that you should stick to measuring tape as its versatility will help you in having accurate calculations for the item.

When you are selecting a measuring tape, ensure that it has a sizable length that shall let you get the exact results.

  • Step-2 (The Measurements)

Now, when you are taking the measurements, the first and foremost thing that you have to do is make sure that the bag is properly stretched, so there is no crease, seam, or anything to hamper your measurements.

Next, fix the top of the tape to one end of the bag, and measure to the other end. Generally, there is a hook on top of the edge of the tape, which shall enable you to measure the dimensions effortlessly! And, to increase the accuracy, take a couple of length measurements, and then average them out.

Using Volume Ratings

Well, in this, there is no need for you to measure the volume as the information should be provided to you on the day of purchase. However, if you don’t remember or didn’t pay much attention to the number of liters the backpack could accommodate, then there is a simple method that you could figure that out!

  • Step-1 (Measuring)

The interesting thing is that to calculate the liters that your backpack offers, you would follow similar steps (like the one we used to measure the dimensions) to calculate the liters. So, let us start from scratch all over again!

First, you would measure the height of the backpack using your measuring tape. Remember to measure the height from different parts of the bag, which would give you various lengths for height, and then take an average. Such a process reduces the chances of anomalies and reduces the percentage error.

Repeat the same process for both width and length. Now, when we are estimating the dimensions, we simple leave these measured parameters as LxHxB, such as 7-inch x 3-inch x 9-inch. Now, we can leave it like that, or we could actually multiply these that will leave us with cubic meters/inches and then convert the results to litres.

  • Step-2 (Converting to Liters)

Once you have volume, all you need to do is convert that into liters:

1 Cubic Meter is equivalent to 1000 liters.

The comparison above shall enable you to do the task more effortlessly. Furthermore, it is not mandatory that your ruler or tape measure is in cubic meter! It could be in centimeters (1 cubic centimeter is equivalent to 0.01 liter), or in inches (1 cubic inch is equivalent to 0.0164 liters).

liter to cubic inch

After you are done with this conversion, you have the specific number of liters that your backpack is competent enough to accommodate.

Comparison for Various Liter Ratings

To make comparing between actual dimensions and liters easy, here are some comparisons that you could use:

  • An 8-liter backpack has dimensions around 17” x 8” x 5”.
  • If you have a 25-liter backpack, then its dimensions are 21” x 11” x 6.5”.
  • The 30-liter backpack should have measurements of 21″ x13.5″ x 9.5″.
  • A backpack with dimensions of 21” x 14” x 9” shall have a volume capacity of around 40-liters.
  • 29.5″ x 13″ x 10″ is the dimensions for a backpack with a volume limit of around 50-liters.
  • A 28″ x 14″ x 12″ backpack provides a liter rating of around 70-liters.
  • 110-liter is equivalent to 30” x 18.5” x 12.5” in dimensions.

To help you understand what rating of liters or dimensions you need, we have provided you a couple more recommendations.

  1. 0-10 Liters backpacks: They are ideal for a light hike, jogging, or any time you need a light profile bag.
  2. 10-25 Liters Backpacks: These are the best for snowboarding trips, hike trips, or various trips where you are going out for a day. You can use them for official purposes as well.
  3. 26-40 Liter Backpacks: They are perfect if you are planning to go for a long trip on the outskirts or something similar.

Why Is It Important to Measure the Size of Backpacks?

The size of the backpack determines various aspects, so we’ve listed them down to show you why it is so important!

Number of Things That You Could Carry

Well, it is true if you take accurate measurements, then you would be able to tell exactly the number of things you can carry. The comparison here shall enable you to decide how to use your specific backpack.backpack dimension

  • Daypacks or Simple Backpacks

These generally have a liter rating of 8 to 25 liters, which makes them a fine option for short hikes, jogs, or just a simple means of carrying the bare essentials.

  • Overnight Packs

As the name suggests, you use these packs when you are planning to stay somewhere ‘over the night’ and can range from 30 to 50 liters. These are spacious enough to hold tents, sleeping bags, and other essential tools for the stay.

  • Weekend Backpacks

Planning to go out for a trip at the weekend? Well, if you are, then you need these types of backpacks. Commonly, these have a range from 30 liters to 70 liters, making them a great option for carrying those extra essentials for the trip.

  • Multi-Day Backpacks

Now, these are the big guns of the backpack world, and if you are going out on a multi-day hike, trip, or vacation, then you need these. They have a range of 50 to 110 liters, which lets you be completely ready for several days when you are out on a trip.

Choosing the Right Backpack

Isn’t it obvious, the bigger the dimensions, or the higher the liter rating on the backpack, the pricier it is going to be! So, when you are purchasing a backpack, understanding these factors will help you in making the correct choice.

For instance, you need a weekend backpack, but as you don’t have a clear understanding of the dimensions or volume of the backpack, you might end up purchasing the wrong kind, which is a waste of time and money.


Having a clear knowledge of how to measure backpack dimensions should help in selecting the right product for the task, give you a clear idea about the number of things that you can fit inside it, and various other things. And, this entire process is made highly effortless, thanks to our article.

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