How to Choose a Backpack

When searching for a new backpack, we’ve done hours of research trying to decide which pack to purchase. Some of my trips take me traveling around the world and some have me headed to the mountains or the desert for a weekend adventure. The two most important things to consider are the trip length and your torso length.

How to Find Your Torso Length

If you don’t know your torso length, you can go into any REI (or similar sporting goods store) and get fitted, or you could have a friend assist you. Here’s how you do it:

  • You’ll need a flexible tape measure.
  • Have your friend start at the bony bump at the base of your neck by tilting your head forward.
  • Place your hands on top of your hip bones with your fingers pointing forward, thumbs in back. You’ll imagine a line drawn between your thumbs in the bottom of your torso.
  • Using the tape measure, your friend should measure the distance between the bony bump at the top and the imaginary line between your thumbs. Be sure you are standing up straight when being measured.
  • You now have your torso length


Below is REI’s general guide to how manufacturers typically size their packs:

Men’s and Women’s
Pack SizeTorso Length
Extra smallUp to 15½”
Small16″ to 17½”
Medium/Regular18″ to 19½”

Most packs offer adjustable and some offer interchangeable hip belts, making it easy to swap one out for another. But it’s good to know your hip size before purchasing a new backpack. Using the same tape measure, wrap it around the top of your hips. You’ll measure at the imaginary line that starts at your belly button to the sides of your hip bones, which is slightly higher than your waist. A properly positioned hipbelt will straddle your hips about an inch above and below that imaginary line.

How to Choose the Right Capacity

The capacity of a backpack is the space inside the pack that is measured in liters and is usually indicated in the packs name (i.e. the Osprey Kyte 46 pack is 46 liters). The trick is making sure it’s big enough to carry your things, but not too big and bulky that it becomes a burden.

Below is REI’s general guide for which pack sizes typically work well for different trip lengths. You should think abut the types of trips you’ll do most often as well as the season. If you plan to use your backpack mostly during the cooler seasons, a larger capacity backpack is probably a better choice for you.

Type of tripPack capacity (liters)Empty pack weight (lbs.)
Day or overnight (1-2 nights)20-501.5 to 4.5
Weekend (2-3 nights)50-602.5 to 5
Multiday (2-5 nights)60-802.5 to 5+
Extended (5+ nights)80+4 to 6+

You should also consider your gear when choosing a backpack. Do you have old, heavy gear or do you have new, lightweight gear? Most of the weight you carry will be around the hips, so you’ll want to choose a padded belt to make supporting the weight more comfortable. Padded shoulder straps are also a bonus!  Both the hip belt and shoulder straps should be adjustable. I also recommend choosing a pack with a contoured, padded lumbar shape to help distribute the weight more evenly. It creates a small space between your back and the bag allowing air to move through and help keep you slightly cooler. You can personalize your pack fit by choosing a backpack that has adjustable suspensions, load-lifter straps, stabilizer straps, and sternum straps.

Other Things to Consider When Choosing a Backpack

Material and Durability – Backpacks range from super thin and light-weight to heavy duty and rugged fabric. Are you more into comfort & durability or weight savings? Unless your goal is ultra light trekking, go with a medium-weight fabric. Rock climbing packs should be even more rugged.  It’s just as important to find a pack that is made of weather resistant fabric. It doesn’t need to be 100% waterproof, but you don’t want your things to get wet in a drizzle. Many packs now come with rain covers (can also be purchased separately), which could be substituted for a plastic garbage bag. If you expect rain on your trip, this is a good item to carry.

Multiple Compartments – Accessing your gear depends on a pack’s configuration. A good pack will have multiple compartments: a main compartment, pockets, side zippers, front zippers or front panels, a sleeping bag compartment, top lid, and attachment points (for attaching trekking poles, an ice axe, etc). This allows you to break up your stuff into smaller sections to make it easier to access.

Hydration – Nearly all packs offer an internal sleeve to hold a water bladder with a convenient hole for the drinking hose to go through.

Ventilation – When a pack rides directly on your back, it cuts off air flow and causes you to sweat. Be sure to choose a pack that has tension-mesh suspension so that your back rests against a mesh-only back panel, which improves breathability.

Lockable Zippers – When traveling, it’s important to make sure that each compartment has two zippers so you can lock them together.

How To Load Your Backpack

backpackYou should first spread our your gear on a clean surface so that you can visually see everything that you need to pack. I also recommend using a checklist to make sure you’ve got everything.

The diagram to the left shows the standard parts of a pack. Virtually all backpacks have a large opening at the top and are known as top-loading packs. Occasionally, they have a zippered sidewall flap known as a panel-loading pack. Your sleeping bag goes in the zippered opening at the bottom. The bottom of the pack is also a good place for other items you won’t need until you arrive at camp such as underwear, sleepwear, a pillow, and maybe a sleeping pad.

Your heaviest items should be placed on top of your sleeping bag and close to your spine. Usually these items will consist of food, water, mess kit and stove. Make sure these items are centered in your pack, not too high and not too low. If you are trekking, you will most likely have porters to carry this gear for you, so all you’ll need  to worry about is your required clothing.

Keep your frequently used items such as GPS, sunscreen, sunglasses, headlamp, bug spray, first-aid kit, snacks, and rain gear, within easy reach.

Packs typically provide external straps, loops, and side pockets, which can be used for your trekking poles, sleeping pad, ice axe, and other tools.

Need to know more? Check out REI’s Expert Advice on how to choose a backpack.

The following are some reputable backpack brands:

REI – Specializes in hiking and traveling specific gear and a wide range of backpacks
Osprey – Stylish, lightweight outdoor packs
North Face – Mountain Hiking backpacks and daypacks
Eagle Creek – Specific travel backpacks and accessories
Gregory – Comfortable, sturdy packs that cater towards mountain hiking

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