Hands cinching a backpack hip belt over the hip bones, torso view only

Guide · Packs

How to fit a backpack

Updated October 5, 2026

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Measure your torso from the C7 vertebra to the top of your iliac crest. That number picks the pack size. The hip belt should sit on the crest, not on your stomach. Load the pack with 20 to 25 pounds before you decide it is comfortable.

Torso length is not height

Two people who are the same height can have different torsos. A pack sized for height alone often puts the shoulder straps in the wrong place, and then every feature review is irrelevant. Use the brand's size chart after you measure.

The hip belt carries the load

If the padding is on your stomach, the shoulders will hurt. Tighten the hip belt first, then the shoulder straps, then the load lifters at about a 45-degree angle. The sternum strap is a stabilizer, not a weight bearer.

Then pick liters

After the fit is right, match volume to the sleep system. A compact quilt kit can live in 50 liters. A bulky synthetic bag may need 65. Empty space will be filled with things you do not need.

Gear for this guide

A 65-liter pack with a suspended mesh back standing on trailhead gravel

PacksOsprey Atmos AG 65Hot-weather miles with a normal multi-day loadAbout 65 L · Moderate for a 65 · Mid to upperOn Amazon

A heavily pocketed 65-liter load-hauling pack standing on trailhead gravel

PacksGregory Baltoro 65People who live out of the lid and pocketsAbout 65 L · Similar class to a featured 65 · Mid to upper

A lighter framed 58-liter pack standing on trailhead gravel

PacksOsprey Exos 58A disciplined kit that does not need a burly frameAbout 58 L · Lighter than a traditional 65 · MidOn Amazon

FAQ

Can a shop fit me?

Yes, and it is worth it for a first expensive pack. Take your heaviest typical load or ask them to weight it.

What if I am between sizes?

Prefer the size that puts the hip belt on the crest. Adjustable harnesses exist for a reason.