How do you measure torso length for a backpack?

Torso length for a backpack is measured as the straight-line distance down the spine from the C7 vertebra to the iliac-crest line, using a flexible tape measure while standing in a natural, upright posture.

Finding the two landmarks

Tilt your head forward to feel for the C7 vertebra, the prominent bony bump at the base of the neck where it meets the shoulders — it stays raised even once the head is upright again. For the iliac crest, place both hands on the waist with thumbs pointing backward and slide down until the thumbs catch the top ridge of the hip bones, then picture a line connecting that ridge across the lower back.

Taking the measurement

Have a helper hold a flexible cloth or vinyl tape measure at the C7 point and run it down the curve of the spine to the iliac-crest line, reading the result in inches or centimeters. A rigid tape measure will straighten the line instead of following the spine's curve, producing an inaccurate, shorter number.

Common torso-length ranges

Most adult torso lengths fall into roughly these bands, though every brand's own chart is the authority for its packs:

Height is not a substitute for this measurement — two hikers of the same height can have noticeably different torso lengths, since torso-to-leg ratio varies by individual, not by overall stature.