How to Properly Fit a Backpack? | The Hipbelt-First Method

For the full breakdown, see our best Women’s Gym Backpack guide.

Sliding on a pack and tugging the shoulder straps is how most people get it wrong. The difference between a comfortable day on the trail and a miserable one with aching shoulders usually comes down to whether the weight sits on your hips. The right way to fit a backpack follows one rule: the hipbelt does the heavy lifting, and the shoulders only stabilize the load. Here is how to get it right, using the method REI and Gregory recommend.

Measure Your Torso Length First

Backpacks are sized by torso length, not your overall height. To measure it, find the C7 vertebra — the prominent bump at the base of your neck — and the iliac crest, the top ridge of your hip bones. Measure straight down the spine from C7 to the line across the top of the iliac crest. Gregory’s sizing chart gives a useful reference: XS fits torsos up to about 15.5 inches (39 cm), and Small fits 16–17.5 inches (41–44 cm). Other trusted sources follow a similar pattern, with Small around 16–19 inches, Medium at 18–21 inches, and Large at 20–23 inches. When between sizes, the fit test with a loaded pack will tell you which works better.

Load the Pack Before Adjusting

Fitting an empty pack is a waste of time; a pack settles differently under load. REI recommends testing with 15–20 lb; Gregory suggests 10–20 lb; The North Face calls for 10–15 lb. Load the pack with your actual gear or anything heavy, then loosen all adjustment straps — shoulder straps, load lifters, sternum strap — so the pack hangs naturally before setting anything.

Adjust in This Order: Hipbelt, Shoulders, Load Lifters, Sternum Strap

The sequence matters because each adjustment builds on the previous one. Here’s what each step should accomplish:

• Hipbelt: Position the padding to hug the top of your hip bones. Gregory says the top edge should sit about 1 inch above your hips; The North Face says it should straddle the hip bones. Tighten firmly but not restrictively. A belt too high can press on the diaphragm and restrict breathing.
• Shoulder straps: They should lie flat and wrap closely around your shoulders without touching your neck or leaving a big gap. As a rule, they should begin about 3 inches below the top of your shoulders. Snug them to stabilize the pack, but you should be able to slide a finger or two under the straps — if they feel like they’re carrying the weight, loosen them and check the hipbelt again.
• Load lifters: These small straps at the top of the shoulder straps should be pulled to about a 45-degree angle, as both Gregory and The North Face recommend. They draw the pack closer to your body and keep the weight from pulling backward.
• Sternum strap: Fasten it across your chest to pull the shoulder straps inward. Adjust so your chest expands naturally and arms move freely — not so high it presses on your throat or so low it restricts breathing.

Common Fit Mistakes and the Final Check

Common mistakes include wearing the pack too low, setting the hipbelt on top of the hips instead of around the iliac crest, skipping the weight test, over-tightening shoulder straps, and adjusting everything at once instead of following the order above. When you’ve got it right, the pack should feel balanced — no pinching, restricted movement, or hitting your head when you look up. Squat down to ensure nothing cuts off circulation. If shopping for a gym pack rather than a trail pack, the fitting logic changes — no hipbelt or load lifters needed. Size it to your gear instead, and if weighing options, our roundup of the top womens gym backpack picks is a good place to start.

Fitting a hiking pack well takes about ten minutes with a proper load. Measure once, adjust in the right order, and the difference in comfort is immediate.