How do you fit a hiking backpack?

By Dana Okoro, Editorial Director · Updated August 31, 2026

Direct Answer

Fitting a hiking backpack starts with measuring torso length and hip size to pick the correct frame and hipbelt size, then loading the pack with realistic weight and adjusting the straps in order: hipbelt first, shoulder straps next, then load lifters and sternum strap. A correct fit puts most of the load on the hips, not the shoulders.

a step demonstrating: How do you fit a hiking backpack, hands and gear only, no face

Fitting a hiking backpack is a two-part process: choosing the correct size using body measurements, then adjusting a loaded pack's straps so the fit actually works on the trail.

Step 1: Measure before choosing a size

Torso length — measured from the C7 vertebra at the base of the neck to the iliac-crest line at the top of the hip bones with a flexible tape measure — determines frame size. Hip circumference, measured around the same iliac-crest landmark, determines hipbelt size. Both numbers are compared against the specific pack's own chart, since size labels vary between brands.

Step 2: Load the pack before adjusting it

An empty pack fits differently than a loaded one, since weight changes how the frame sits against the back. Fill the pack with something close to a real trail load — 15 to 25 pounds is enough to reveal fit problems — before making any strap adjustments.

Step 3: Adjust in the correct order

Hipbelt first. Center the belt over the hip bones and tighten until it carries the pack's weight without shifting.
Shoulder straps second. Snug them so they wrap the shoulders without gaps, without taking over load the hipbelt should be carrying.
Load lifters third. These small straps above the shoulders should pull at roughly a 45-degree angle from the pack to the shoulder, angling the load in toward the back.
Sternum strap last. Positioned an inch or two below the collarbone, tightened just enough to keep the shoulder straps from sliding outward.

Working through how to adjust a hiking backpack's straps in this order, rather than randomly, is what turns a correctly sized pack into a comfortable one — a pack that's the right size but poorly adjusted can still hurt.

Signs the fit is off

Shoulder pain usually means the hipbelt isn't carrying its share of the load; lower-back pain often points to a frame that's too long or too short for the measured torso length. Both are reasons to re-check the measurement before assuming a different pack model is needed.