If your shoulders ache after a hike, the pack is probably sitting wrong. The fix begins before you even strap in: you have to measure your torso, not your height. That number decides which pack size you buy, and it sets up everything else about the fit. The whole process takes about ten minutes and changes how a load feels on a long trail.
Measure Your Torso Length First
Torso length drives backpack sizing, and it has nothing to do with how tall you are. REI’s fitting guide says to find the bony bump at the base of your neck — that’s C7 — then place your hands on the top of your hip bones to locate the iliac crest. The distance between those two points is your torso length.
To measure it yourself, tilt your head forward so the C7 vertebra stands out, put a finger on it, then measure straight down to the line of your hip bones. Stand naturally with a relaxed spine. A second person makes this easier but isn’t required.
You can then compare that number to the brand’s size chart. Example ranges from non-manufacturer guides run roughly: XS up to about 15.5 inches, S 16–17.5 inches, M 18–19.5 inches, and L over 20 inches. Those figures vary across brands, so the manufacturer’s own fit chart for the exact model is what you should trust. If you land between sizes, try the pack on with weight in it before deciding.
The Load Split: Hips Take Most Of It
If the straps are doing the heavy lifting, the pack is fitted wrong.
That split only works when the hipbelt sits correctly. The belt should straddle the iliac crest — the bony knob on top of your hip bones — not your waist. When it is snug, the padded portion wraps well around your hips.
Buying the right size hinges on this measurement, so it is worth the few minutes before you shop. A pack with the wrong torso length simply will not place the belt where it needs to be.
Adjust With Weight In The Pack
Fitting an empty pack tells you nothing. The North Face recommends loading the bag with roughly 10–15 pounds before you adjust anything. Gregory’s guidance runs 10–20 pounds, and MEC suggests about 8–10 kilograms. The load changes how the straps sit, so tune the fit with the weight you’ll actually carry.
Set The Straps In This Order
When the pack is loaded, give each strap one pass rather than bouncing between them:
- Hipbelt first. Tighten it until it feels secure and snug over your hip bones without restricting your breathing. This is the load-bearing strap.
- Shoulder straps second. Snug them so they lie flat and wrap closely over your shoulders. MEC adds that straps should not touch your neck, and you shouldn’t see a large gap at the top of your shoulders. They should not carry the bulk of the weight — the hips do that.
- Load lifters third. Pull these to roughly a 45-degree angle to bring the top of the pack closer to your back.
- Sternum strap last. Fasten it across your chest so it relieves shoulder pressure while still letting you breathe and move your arms. MEC says to adjust it so your chest can expand naturally.
The most common mistakes all trace back to skipping a step: wearing the hipbelt on the waist instead of the hip bones, letting the shoulder straps take too much load, or setting the load lifters at the wrong angle. Fitting an unloaded pack is another frequent miss.
This process targets hiking and backpacking-style packs with adjustable suspension systems, not every daypack. Some models let you shift the hipbelt height; others don’t. If the pack you’re considering won’t put the belt on your hip bones with the torso length right, it’s the wrong model for you.
Once your pack fits correctly, the next question is whether it suits your daily routine. Many people want one bag that handles both the trail and the commute. Our roundup of top commuter-friendly gym backpacks covers tested options that carry laptops and workout gear without sacrificing comfort.
Fit Checklist For Your Next Trip
Before you head out, run through these in order with weight in the pack:
- Hipbelt sits on the hip bones, snug but not restrictive.
- Shoulder straps lie flat, clear of your neck, carrying only about 20% of the load.
- Load lifters angle at roughly 45 degrees, pulling the pack close to your back.
- Sternum strap fastens without limiting your breathing or arm swing.
A few minutes of tuning turns any long day into a lighter one — and keeps the strain off your shoulders where it used to land.
FAQs
What if my torso length falls between sizes?
Between sizes, the safer pick depends on the pack’s suspension, and brand charts vary widely. Most outfitters recommend trying the pack on in person with some weight in it. It is also worth checking whether your chosen model allows hipbelt height adjustment, since that can sometimes bridge the gap.
Why does my neck hurt when I wear a backpack?
Neck pain usually means the shoulder straps are carrying too much weight or the pack is sitting too low on the torso. Adjust the hipbelt so it holds the load on your hip bones, then set the load lifters to about 45 degrees to bring the pack higher and closer to your back.
Should I tighten the hipbelt as hard as possible?
No. The belt should feel secure and snug, but it should never restrict your breathing or dig into your hip bones.
References & Sources
- REI. “How to Fit a Backpack.” Explains torso measurement, the 80/20 load split, and hipbelt positioning.
- The North Face. “How to Fit and Wear a Backpack for All-Day Comfort.” Details the weight distribution and strap adjustment order.
- MEC. “How to Choose and Fit a Backpack.” Covers load weights for fitting, sternum strap position, and shoulder strap clearance.