Being Nomadic is a reader-supported blog. When you purchase anything via links on our site, we may earn an affiliate commission without costing you anything extra.

How to Measure a Backpack in 2021: Best Guide for All

The need for backpacks is unavoidable, be it for daily activities or certain trips or hiking. And we know it, backpacks are available in various shapes and sizes. That is why sometimes we cannot find the perfect backpack for us because they are not always the same as they are shown.

It is essential to know how to measure a backpack before any trip or hiking. You don’t want to have a bad experience while you are trekking with your close ones.

Some of the basic things that you need to keep in mind while measuring are the backpack’s volume and dimensions.

how to measure a backpack
How to Measure a Backpack (Proven Methods)

 How to Measure a Backpack Size?

If you think of measuring your backpack, there are ways to measure different types of bags. Measuring backpacks give you an understanding of the requirements and how it can be useful. So, let us talk about how to measure the dimension and the volume of the carrier.

Measuring Actual Dimensions

The company or the brand has the authority to provide the buyers with the details of the measurement. Depending on the unit (Liters, cubics inches or both), the measurement process becomes easier.

Some of the manufacturers provide both the unit, which becomes simple for the users. It is mandatory to mention the actual dimension of the bag as it determines the size and the proportions.

All you need to do is, take a measuring tape and start to find the interiors of the backpacks. Finding the length, the height and the width helps you choose which bag will fulfil your purpose.

Measuring Volume

Other than measuring the dimension, you can also find out the backpack’s capacity by measuring the volume. As we know, volume defines the total space ( the three-dimensional capacity).

Therefore when we measure the volume, we measure usable space in the bag. It can determine how many things we can keep while we trek.

We can measure the volume by multiplying the figures given by the manufacturer. Generally, the volume is expressed by litres which is useful and more accurate while calculating the number of things you plan to keep inside the bag.

measuring a backpack size
How to Measure a Backpack Size?

Why is Backpack Size Important?

To find your perfect hiking or travelling buddy, you need to understand the importance of size. They determine the capacity and circumscriptions, and Investing in a bag should be your primary priority.

Your experience and how much weight you can carry depends on the size and the requirements of the bag. For instance, if the bag does not sit great in your needs, later it can cause health issues, including back pain or spine damage.

And in some extreme cases, the incorrect size and capacity of the backpack can make you stumble during a trek. It is crucial to understand which backpack is comfortable and safe for you when hiking or trekking.

Before learning how to measure a backpack, you should also know about some standard backpack sizes as well.

Some Standard Backpack Sizes

Your choice of backpack lies in the type of adventure and the days spent outdoors. Be it a day trip or camping for a month, the most important thing to consider is how much your backpack will carry and is enough?

To answer the question, we will list below a table for some standard sizes of the backpack in the form of a table. It will give you a better idea because it includes the size, features and limitations.

Volume/Dimension FeaturesLimitations
8L / 17’’ x 8’’ x 5’’It is lightweight and consists of rain covers. Contains several small compartmentsThe essentials can only last for a few hours.
25L / 21” x 11” x 6.5Generally, daily backpacks fall in this category. Consists of insulation fabric layersThe backpack can only carry the food sources only for a day.
30L / 21″ x13.5″ x 9.5Can keep sleeping pads. Includes multiple compartmentsIdeal for an overnight trip
40L / 21” x 14” x 9

Almost carries everything. Can carry food for days, small stove and clothes easily.
Limit upto few days of trip or hiking.
50L / 29.5″ x 13″ x 10″Can hold extra things like tents, different shoes for different purposes.Best for a weekend trip with more than 3 people.
70L / 28″ x 14″ x 12″ It is generally used for hikers who go hiking for 10 days. It has additional space for expendable items for a better experience.It can carry upto 10 days worth
100L / ‎30” x 18.5” x 12.5” It is for high altitude trips. They are highly insulated with space for sleeping essentialsThe limit is the weight you can carry while travelling.of essentials.

Common Hiking Backpack Sizes and Uses

After understanding the dimension, features, and limitations, we need to know the common trekking backpacks. Their sizes and under what circumstance one can use them.


  • They usually come in 8L to 25L of volume
  • Ideal for few hours trip or trekking
  • Can carry some essential which can last a day
  • Consist in some small compartments to keep snacks and water bottles.

Weekend Backpacks

  • They usually come in 50 liters to 70 liters of volume.
  • Ideal for weekend hiking
  • The essentials can last up to 2 days.

Multi-Day Backpacks

  • Comes in 50 liters to 110 liters of volume
  • Can carry tents, sleeping pads, small stove and food.
  • One can use it for overnight trips or short hiking trips.

Carry on backpacks

  • If you have back pain issues or want to be comfortable while travelling, this is the best one.
  • Comes in 40liters to 50 liters of volume.
  • They avoid the hassle through airport security.

Hydration backpacks

Hydration backpacks
  • They are known for comfort and easy to grip designs.
  • Since they have multiple compartments, it gives you easy access while hiking.
  • As its name suggests, it has an extra water capacity.
  • It is best for recreational purposes where the need for water is frequent.

Female-specific backpacks

  • Generally, backpacks are unisex, but this category is different as they fulfil some specific needs for women.
  • They are designed especially for women as the features of women are different from men.
  • They have a waist belt for better grip and have a short upper body length.
  • Makes it easier for women to enjoy hiking rather than worrying about the backpack.

How To Choose The Right Sized Backpack For You

Since we know how important it is to find the right size of the backpack, we should consider some factors before choosing the right one among hundreds of backpacks available in the market.

Many styles and designs offer various features and making a decision can be confusing sometimes. That is why there are some factors listed below so that the process of choosing becomes easier.

Your Body Type

Before choosing the perfect bag, you need to understand what your body type is and how long your torso is. So it is required to make sure that the back fits with your torso, and to that, you need to measure your length, hip size and try to adjust the length of your torso with the backpack.

How To Choose The Right Sized Backpack For You

Measure Your Torso Length

Bend down, and you will notice a bump behind your neck. It is known as the cervical vertebra, and from there, the gap of the backpack starts and determines the upper torso. Make sure to measure the length between the neck and the shoulders.

Measure Your Hip Size

Here all you need to do is, measure the length of your hip that is you measure the tape around the hip. This is important because most of the weight( almost 70 to 80 percent of weight) lies on the hip and that is why understanding the perfect fit is required.

Adjusting Torso Length

This time you will need help from your friend. It would be best to ask any of your friends to calculate the gap of the back to determine the length of the torso.

Weight Capacity

You need to keep one thing in mind: how much weight can you generally carry while hiking? This also determines the limit of your ability to carry. You should carry a bag which helps to distribute the weight evenly.


Different backpacks serve different purposes depending on the weather. Trekking and long trips include getting wet during the rainy season or hiking during winter. Fabric plays an important role as they need to protect from the sunlight or extremely cold weather.

Your packing style

Some of us pack our belongings in unique ways. Some people prefer to roll their clothing, while others prefer to fold them. That is why, if you fold your clothes, you will need a larger backpack, and if you roll the clothes, you need a small bag comparatively.

How To Adjust Your Backpack Fit At Home

If the backpack is new, then you need to make several adjustments. Various straps provide different needs. The main objective of the straps is to adjust the body so that the weight gets distributed on the hips.

Step 1: Hip belt

Put on your backpack and adjust your back comfortably. Now, for instance if the bag is too high or low, then you can adjust it accordingly.

 Make sure the strap around the hip is fitted in the proper position so that your journey becomes comfortable. Later, when needed, tighten or loosen as you wish so that the padding gets evenly set.

How To Adjust Your Backpack Fit At Home

Step 2: Shoulder Straps

The straps that are attached around your shoulder slope are known as shoulder straps. They help you to keep balance and avoid the entire weight of the back on one point. You need to adjust the straps to find your comfort spot while hiking.

Step 3: Load Lifters

The purpose of the load lifters is to make sure the load of the bag is evenly distributed. They help you to keep the bag stuck to your body more if you tighten it. If not adjusted securely, it can cause pain on your shoulder after some time and can cause instability.

Step 4: Sternum Strap

If you want to reduce the stress and try to distribute the weight around the back, sternum straps do that for you. Make sure not to tighten the straps too much, which can cause problems in breathing.

How To Adjust Your Backpack Fit On The Trail

While on a hiking trip, you will need to adjust your backpack at some point. And the process of acquiring the comfort zone with the backpack is long and needs constant attention.

Often taking a break is required and removing the backpack gives the muscle some time to relax. The time you get your backpack, make sure to adjust according to your need and give time to understand the working of the strap.

There are many ways one can alter the backpack fit during the trail is to use the hit and trial method. Learn from your mistakes and correct the straps to be comfortable while hiking.

Also Read: Osprey Tropos vs Nebula Backpack (Comparison)


Whether you are an adventurous type or not, the need for a backpack is inescapable. Bags are required to carry and store your essentials whenever and wherever you go.

 I hope this guide on how to measure a backpack will help you to decide which bag is best for you. If you get your best buddy, this article will give you the appropriate information to acquire the best experience while trekking.

Rocky D

Leave a Comment