By Dana Okoro, Editorial Reviewer · Published September 14, 2026, 6:03 PM ET · Updated September 29, 2026, 6:16 PM ET
Direct Answer
Size a women's-fit hiking backpack by measuring torso length from the C7 vertebra to the iliac crest, then matching that number to the specific brand's women's size chart rather than its unisex chart. Load the pack and confirm the hipbelt centers on the hip bones and the shoulder straps sit flat with no gap at the collarbone.
In plain English
Backpacks come in sizes, but not like clothes. The size depends on the length of your back, called your torso, not how tall you are or what size jeans you wear. Two people of the same height can need different pack sizes.
To measure, tip your head forward and feel for the bump at the base of your neck. Then put your hands on your hips and find the top of your hip bones. A friend measures down your spine between those two points. That number is your torso length.
Packs made for women are often shaped differently too. The shoulder straps may be narrower and curved, and the hip belt may be angled to fit wider hips. Still, the best fit is the one that feels right on your body, so try the pack with some weight in it before you decide.
Torso length, not height or clothing size, determines how a women's-fit pack sits on the body, since two hikers of the same height can have torso lengths that differ by two inches or more.
Step-by-step measurement
Tilt the head forward and find the C7 vertebra, the bony bump that protrudes most at the base of the neck.
Place both hands on the hips with thumbs pointing toward the spine to locate the iliac crest, the top of the hip bones.
Have a second person measure straight down the spine with a flexible tape, from the C7 point to the line between the thumbs.
Record the number in inches and compare it against the specific brand's women's chart, since the same measurement can land in a different size tier depending on the manufacturer.
What the number typically means
Torso length
Typical women's-fit size
Under 14 in
Often below standard range; check petite or short-torso sizing
14–15.5 in
Extra-small
15.5–17 in
Small
17–18.5 in
Medium
Chart boundaries shift by half an inch or more between brands, so treat this as a starting point rather than a universal rule.
Confirm the fit under load
Load the pack with a few pounds of gear before judging fit, since an empty pack won't reveal how the hipbelt and straps behave once weight settles in. The hipbelt padding should center directly over the hip bones, not ride up onto the waist or slip down onto the thighs, because a correctly centered hipbelt is meant to carry most of the total load. Shoulder straps should wrap the shoulder without gapping near the collarbone, and load lifters should sit near a 45-degree angle from the shoulder to the pack body. A hiker who measures between two sizes should size down on a fixed-frame pack or set an adjustable suspension to the middle of its range, then fine-tune after this loaded check.
What actually changes in a women's-fit pack
Women-specific packs are built around a different fit, not just a smaller size. Deuter says its SL (women's) packs use narrower S-shaped shoulder straps and conically shaped hip fins, and its SL fit targets a back length of about 42 cm for body heights of roughly 160–175 cm, compared with about 46 cm for its regular fit and 50 cm for EL.1 Granite Gear says its women's hip belts are built for hips with a greater angle than unisex belts.2
Hip-belt sizing can differ too. ULA sizes women's hip belts by adding 5 inches to the smallest waist measurement for curvier proportions, or 3 inches for straighter builds, and offers S-straps for sloping shoulders and J-straps for flat or square ones.3 Not every brand splits by gender: Gregory sizes packs identically regardless of gender, so its medium is the same torso size in men's, women's and unisex packs.4 A women's label tells you about shape; the torso number still decides the size.
Why this page's size chart is only a starting point
The chart on this page is a general guide, not one brand's published sizing, and the page rightly says boundaries shift between makers. Granite Gear, for example, uses Short (15–18 in), Regular (18–21 in) and Long (21–24 in) torso sizes.2 Even the measurement can differ: Mystery Ranch measures from C7 down to a point just behind the belly button, not the top of the hip bones, and recommends sizing down if you fall between sizes.5
Measure rather than guess from height. Hyperlite says height is not a reliable proxy for torso length,6 and Kelty says a torso measurement is only a starting point for fit.7 Deuter adds that even adjustable packs should be chosen in the correct back length,1 because an adjustable harness works best near the middle of its range.
Checking the fit under load
The page suggests loading a few pounds before judging fit. Big Agnes goes further and suggests fitting a pack with 10 to 20 pounds loaded.8 Deuter says to center the hip fins over the top of the hip bone before fastening the belt,9 and Osprey says a correctly sized hipbelt leaves a 3–6 inch gap between the pad tips when tightened.10
Sources give ranges for the upper straps. Big Agnes sets load lifters at 45 degrees,8 Deuter says they work best between 30 and 45 degrees,9 and Alpkit gives 25–45 degrees from horizontal, with the sternum strap about an inch below the collarbone.11 The page's '80% on the hipbelt' is Big Agnes's target;8 Alpkit says 60–80%,11 and the US Army's manual says about 30% on the hips with a frame and hip belt.12 All agree the hips should carry the main load.
