How to Fit a Backpack for Hiking

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Backpacking and hiking is a great way to see the world, but if you don’t have correct fitting gear it can be uncomfortable and painful. I have definitely worn my fair share of poor fitting backpacks in the past and it is a sure way for a backache or some chaffed shoulders. I do not want you to experience that kind of discomfort on the trail! In this article I will show you how to fit for a backpack so that you can make sure your backpack fits well for your upcoming adventures!

How to Fit a Backpack

When getting ready to measure for a backpack it is important to first locate your starting and end points. Typically, the start point is the C7 vertebrae on your spine and the iliac crest at your hips. Finding these points are crucial for how to measure for a backpack, correctly.

Locating the C7 Vertebra

First, you need to find the starting point of your torso measurement – the C7 vertebra. To do this, stand up straight, tilt your head forward, and feel for a bony bump at the base of your neck, where your shoulders join the beginning of the neck. This is your seventh cervical, or C7 vertebra, which marks the top of your torso.

Finding the Iliac Crest

Next, identify the ending point of your torso measurement by locating the iliac crest. To find the iliac crest, place your hands on your hips with your thumbs pointing towards your back. The point where your thumbs meet along your spine is the top of your iliac crest, marking the end of your torso.

Measure from the C7 to the iliac crest

Measuring Torso Length

Now that you have the two main reference points identified, you can measure your torso length. The most accurate method is to have the help of a friend and follow these steps:

  1. Take a flexible tape measure, not a hard ruler.
  2. Begin at the C7 vertebra and hold the tape measure in place.
  3. Extend the tape measure along the curve of your spine and down to the top of your iliac crest, which you identified earlier.

Record the measurement of your torso length from the tape measure. Make sure it lies over the most curvature parts of the spine to get an accurate reading. Having the correct torso length measurement will ensure that you find a backpack that fits comfortably and distributes the weight evenly across your back, making carrying your gear a more enjoyable experience.

Other Methods to Measure Your Torso Length

If you don’t have a friend to help you out, it is no biggie there are still multiple ways for how to measure for a backpack. The key is to find something that will reach from the base of your neck (C7) to the space just above your hip bones.

Here are some other methods that can be used: 

  • A belt or shoelace: With a belt or shoelace, you can mark the starting point (C7) by placing the belt or shoelace along the bag and feeling with your fingers. Use one finger to keep the belt or shoelace against the C7. Next follow along the belt or shoelace down to the iliac crest and feel where the belt and shoelace are at. At the end you will have used one hand to keep the shoelace or belt in place at the top against the C7 and the other hand to mark the iliac crest placement. Afterwards use a ruler or measuring tape to measure the distance. 
  • A shirt: Another option is to wear a shirt that fits comfortably and measures the distance between the collar and about where your hip bones are.
  • Use a wall, paper, and pen: If you ever used a wall to mark your height growing up then this method will be a piece of cake. Tape about 3 white pieces of blank paper against a wall in the vertical row. Place your back against the paper then locate the C7 and Iliac crest zones. Once located use a pen or pencil to mark it along the paper that was placed on the wall. 

No matter which method you use, make sure that you’re standing up straight and measuring from the same points each time to ensure accuracy. I would be sure to take about 3 measurements and then average them for more accuracy. 

Measuring Your Hip Size

Locate your hip bones

Locating the Hip Bones

To measure your hip size accurately, you need to first locate your hip bones. The hip bones are also known as the iliac crest, which is the upper edge of your pelvis. Start by placing your hands on your hips, with your thumbs at the small of your back. Feel for the bony protrusions on each side; these are the tops of your iliac crest.

Using a Flexible Measuring Tape

Now that you’ve located your hip bones, it’s time to take measurements. Follow these steps:

  1. Place the beginning of the tape measure at the starting point: Use a flexible measuring tape, the kind used for sewing or tailoring, and place it at the top of your iliac crest where you’ve located your hip bones.
  2. Wrap the measuring tape around your body: Carefully wrap the measuring tape around your hips, ensuring it stays level and goes over the iliac crest. Make sure the tape measure is not too tight or too loose, and that it’s not twisted.
  3. Read the measurement: Once the measuring tape is securely in place around your hips, record the measurement to the nearest inch or centimeter.

Remember, always select a backpack that can accommodate your hip size comfortably. That way, when hiking or carrying a heavy load, the majority of the weight will be supported by your hips, allowing for a more comfortable and enjoyable experience.

Choosing the Right Backpack Capacity

Type of Trip

After you have learned how to measure for a backpack. Start thinking about the capacity you might need for your backpack. When determining the appropriate backpack capacity for your needs, consider the type of trip you’ll be taking and the weight you will be carrying. The length and nature of the journey will significantly influence the size of the pack you need.

Here’s a general guide to help you choose the right capacity for various trips:

  • Day trips (0-30 liters): Quick outings or trail runs require a small, lightweight pack just for essentials, like a hydration pack or a small daypack.
  • Overnight trips (30-50 liters): For short, one- or two-night adventures, a mid-sized pack is suitable. These backpacks can hold a lightweight sleeping bag, a change of clothes, and a small amount of food.
  • Multi-day trips (50-80 liters): Longer trips of three or more nights necessitate a larger pack that can accommodate more clothing, food, and gear.
  • Expeditions (80+ liters): Extended trips that involve camping or mountaineering call for a high-capacity pack to carry all the necessary equipment, clothing, and supplies.

What Type of Backpacker Are You? 

Your personal packing preferences will also play a role in determining the ideal backpack capacity. If you tend to be a beginner or want a more comfortable trip, then your pack will be a bit heavier than if you are looking to cover as many miles as possible on the Appalachian trail, where you would want to go a bit lighter.

Consider the following factors when trying to fit a backpack:

  • Trip Objective: Are you planning to focus on hiking, camping, or a mix of both?
  • Minimalist or heavy packer: Do you prefer to travel light, only bringing the bare necessities, or are you more inclined to pack extra gear and comforts? Adjust your backpack capacity accordingly.
  • Load distribution: It’s essential to consider how the load will be distributed on your body, particularly with larger backpacks. Ensure the backpack’s design allows for an even distribution of weight across your torso.
  • Built-in storage: Some backpacks come with additional storage compartments, pockets, or attachment points for organizing and accessing your gear. Consider if this feature is important or necessary for your packing style.

By carefully considering the type of trip and your personal packing preferences, you can select the right backpack capacity to accommodate your needs without unnecessary bulk or weight. Considering your pack weight is a crucial piece in determining the capacity for your backpack. For more information and guidance, read my article about how to find your backpacking weight.

Considering Backpack Dimensions

Height and Width

After you have learned how to size and fit a backpack, you may also want to consider the backpack dimensions. Considering the right backpack dimensions, pay close attention to the height and width of the bag. Here are some common backpack sizes, in liters (L), along with their typical dimensions:

  • 25L backpack: 21″ x 11″ x 6.5″
  • 30L backpack: 21″ x 13.5″ x 9.5″
  • 40L backpack: 21″ x 14″ x 9″
  • 50L backpack: 29.5″ x 13″ x 10″
  • 70L backpack: 28″ x 14″ x 12″
  • 110L backpack: 30″ x 18.5″ x 12.5″

These dimensions represent a general guide and can vary depending on the specific bag and brand. It’s important to note that size is not only determined by the capacity of the bag but also by its dimensions.

How to Adjust Backpacking Straps 

Once you have your backpack, it’s important to make sure that the straps are adjusted correctly. To start, pack your backpack with around 15 pounds of weight to best simulate real weight. After that, you can begin adjusting the straps, so you have a snug fit.

There are four straps that need to be adjusted, of the four the main two are the hip belt and shoulder straps which will vary depending on your torso length. The last two straps, the load-lifter straps and the sternum strap should also be adjusted for optimal comfort. 


Adjust the hip belt first. The majority of the load should be on the hip belt, not your shoulders. The hip belt should rest snugly on your hip bones. It’s important that the hip belt is tight enough to support the weight of the backpack but not too tight that it causes discomfort. 

You can adjust the hip belt by loosening or tightening the straps until you find a comfortable fit. The padding should rest on top of the hip bones. If it’s too low or high, you’ll need to adjust them until they feel just right.

Shoulder straps

Tighten the shoulder straps, making sure they wrap fully around your shoulders with no gaps. The shoulder straps should rest comfortably around your shoulders, making sure that the bag isn’t too low or too high. You can adjust the straps by sliding them up or down until they fit perfectly on your shoulders. 

To start, loosen both shoulder straps all the way. Once they’re loose, you can start adjusting them one by one. Begin by lifting one strap over your shoulder until it’s comfortable. Then, tighten the other strap until the two straps are even on each side.

These straps should not be carrying much weight. If they are, they’ll cause discomfort and strain your shoulders. The hip belt should be carrying most of the weight. If it’s not, readjust the hip belt and double-check that your backpack is the correct length.

Sternum Strap

Next, fasten and tighten the sternum strap, positioning it roughly an inch below your collarbones. This will help set the shoulder straps at a width that allows your arms to move freely.

The sternum strap helps to secure your shoulder straps in place and prevent them from slipping off your shoulders. To adjust, loosen the straps and then pull them across your chest until they fit comfortably. Once you’ve adjusted the straps, tightly secure the buckle in place. 

Load-lifter Straps

Adjust the load lifter straps, so they are at about a 45° angle to the backpack’s body. These straps help pull the weight of your gear closer to your body, relieving stress on your shoulders. 

To adjust these straps, loosen them all the way and then loosen the shoulder straps as well. Once they’re loose, you can tighten the load-lifter straps until they fit comfortably and form a 45-degree angle. Just make sure not to over-tighten them! Remember that you’re going for a comfortable fit. There should not be a lot of tension on the straps.

Once you’ve adjusted all the straps, it’s important to double-check that they are all snug and secure. By following these steps, you’ll achieve a comfortable and secure fit for your backpack, ensuring an enjoyable hiking experience with maximum comfort on the trail. 

Why the Right Backpack Fit Matters 

Having the right size backpack is essential to making sure your backpacking trip is enjoyable, and here’s why:

Comfort: If your backpack is too big or too small, you won’t be able to distribute the weight correctly and it will cause strain on your shoulders and back. This will quickly become uncomfortable, making it hard to enjoy the scenery around you. Above all, you need to prioritize comfort by making sure you have a good size and fit for your backpack.

Stability: An ill-fitting backpack can also make it difficult to walk steadily. This can lead to slipping and falling or throwing off your balance, which can be dangerous on uneven terrain. You ultimately want your backpack to feel stable and not too loose.

Accessibility: Getting to your gear quickly and efficiently is important in any situation, but especially when you’re out on the trail. If your backpack is too big or too small, it can be difficult to find what you need when you need it. 

Energy:  With a backpack that fits correctly, your body can use the energy from your muscles more efficiently. This will help you conserve energy and make it easier to tackle more difficult terrain. If you have a poor fitting backpack you will compensating and using more energy than you need to. Make sure you work smarter and not harder by ensuring you backpack is sized and fits right.

How to Fit a Backpacking Pack || REI
Video for how to fit a backpack by REI

Final Thoughts 

Knowing your torso length and properly adjusting the straps of your backpack is key to carrying it with comfort and ease. Make sure use this guide to fit for your backpack accurately and adjust the straps accordingly. With the right fit, you’ll be able to enjoy all your backpacking adventures without any discomfort or strain. If you need help reflect back on this guide for how to measure for a backpack. Hope to see you out on the trails!

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