Walking through the store you spot the perfect backpack.  After gathering about 15-20lbs worth of stuff to throw inside, you give it a try but something just doesn’t feel right in regards to torso measurement and dimensions.  

Is it the way it fits around your waist?  Does it feel lopsided?  Maybe the weights not distributed properly.  Perhaps this backpack isn’t the right one for me.

All of these questions and hundreds more start rolling through your brain, crushing your cells like a steamroller!  The next thing you know is that you start second guessing yourself on whether or not this is going to be the perfect pack for that 8 months backpacking trip around the world or that simple camping trip in the backcountry of Colorado.

Luckily I’ve created an easy to follow guide on how to fit your pack properly before you even set foot out of the house that way when you step foot into your nearest outfitter store, you’ll know what you’re doing, what you’re looking for, and feel like a pro!

How to Fit a Backpack

Torso MeasurementWhen in hopes of finding the right backpack, you need to perform the following tasks before/while shopping:

  • Measure your torso length

    • To ensure you don’t purchase a pack that’s too large or too small, measure the length of your torso and make sure it matches the length of your potential pack.
  • Set the shoulder harness

    • Set the shoulder harness on the pack according to your torso measurement.  Do this for both the top and bottom slots.
  • Load the pack with gear

    • Once you have found a potential pack and performed the two previous tasks, load it with 15-20lbs worth of gear.
  • Put the pack on

    • Next, you place the backpack on your back.  Tighten the shoulder straps so that they fit snug to your shoulders and then tighten the waist belt so that it is snug too.  The waistbelt should fit snug, resting on your hips.  When positioning all the weight to sit on your hips, it will put less stress on your back and result in less of a chance of getting injured.
  • Simple Exercise

    • Carefully lift your leg until your thigh is at a 90° Angle to the rest of your body.  If the pack is fitted properly, you should be able to easily hold your balance.  At this point, the bottom edge of the strap that’s around your waist should be level to your thigh.
  • Shoulder Straps

    • Once you can hold your balance, lower your leg to the standing position once again and loosen the shoulder stabilizer straps.  Towards the bottom of the harness, make sure there is 1½ – 2½ inches to play with.  The curve that’s in your shoulder straps should be at the same level as your armpit.
  • Shoulder stabilizer straps

    • Lastly, pull the shoulder stabilizer straps on the pack until they are tense against your body.  Be careful not to make them too tight, as this may result in unnecessary strain on your body.
  • Final Adjustments

    • Make any final adjustments to the pack.  The goal here is not so much as worrying about functionality but more so about comfort.  Going on that long backpacking trip around the world with an uncomfortable pack will catch up with you quickly!

Fitting the Frame, Shoulder Harness & Waist Belt

How to measure your torso for frame size-

Measuring with a flexible tape measure, learning how to measure torso is fairly easy. Simply measure the length of your torso by beginning at the base of your neck (the C7 vertebra) to the top of your bony hip structure at the base of your back (called the iliac crest).  

Measure it a few times to ensure that you have the same measurement all the time.  If you measure your torso and are in between measurements, always choose the smaller pack.  The following is a general chart to follow when selecting a pack compared to your torso measurement:

  • 14″ (35.6 cm)          Frame Size-XS
  • 16″ (40.6 cm)          Frame Size-S
  • 18″ (45.7 cm)           Frame Size-M
  • 20″ (50.8 cm)          Frame Size-L

Shoulder Harness Positioning-

It is most likely that when picking out your shoulder harness that the size of it will be similar to your frame size.  But just to make certain that it is the correct size, (just as I mentioned earlier) make sure that the curve is level with your armpit.

  • 14-15 inches (36-38 cm)          Frame Size-XS
  • 16-17 inches (41-43 cm)          Frame Size-S
  • 18-19 inches (46-48 cm)          Frame Size-M
  • 20-21 inches (51-53 cm)          Frame Size-L

Waist belt Size-

When sizing your waist belt, be sure that you lift it up on your waist and tighten snugly on the straps.  There should be approximately 3 – 5 inches of extra strap in the event that you lose/gain weight or your body swells up around the waist during your trip.  Follow this general guideline for sizes:

  • 22-28 inches          S
  • 28-34 inches          M
  • 34 + inches             L

Some Final Words

Ultimately, when choosing your backpack, above all make sure that the pack fits comfortably and that you have measured your torso properly –  I can not stress this enough!  Only when you find a selection of backpacks that fit comfortably, do you narrow your search down to the backpack’s features and, ultimately, the gear you’ll need for your next backpacking trip abroad.

Do you commonly measure your torso, waist and shoulder harness positioning when you fit a backpack? Why or why not?