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2 harnesses · checked 2026-10-21

Climbing harness size by waist

A harness is sized by waist and thigh, not by clothing size. At a 32-inch waist the Black Diamond Momentum reads M and the Petzl Corax 1 or 2. Petzl makes two wide-adjusting sizes; Black Diamond six narrower ones.

50100150200123
  1. 1Climber 32 in waist · 22 in thigh
  2. 2BD Momentum M
  3. 3Petzl Corax 1 or 2
22 in28 in34 in40 in46 inBD Momentum XS24–27 inBD Momentum S27–30 inBD Momentum M30–33 inBD Momentum L33–36 inBD Momentum XL36–39 inBD Momentum XXL40–45 inPetzl Corax 125.5–37.7 inPetzl Corax 229.9–42.1 in
Waist range of every size of the two harnesses, in inches. Where bars overlap, a waist fits two sizes and the leg loops decide.

Size by waist

WaistBlack Diamond MomentumPetzl Corax
26 in (66 cm)XS1
28 in (71 cm)S1
30 in (76 cm)S or M1 or 2
32 in (81 cm)M1 or 2
34 in (86 cm)L1 or 2
36 in (91 cm)L or XL1 or 2
38 in (97 cm)XL2
40 in (102 cm)XXL2

Ranges as REI lists them for each model: Black Diamond Momentum harness, men's (REI product page); Petzl Corax harness, men's (REI product page). Checked 2026-10-21. Centimetres are converted from the printed inches.

Each harness, as printed

Black Diamond Momentum

SizeWaistLeg loop
XS24–27 in17–19 in
S27–30 in17–21 in
M30–33 in21–25 in
L33–36 in24–28 in
XL36–39 in26–30 in
XXL40–45 in26–30 in

REI notes the harness "Fits slightly large based on reviews."

Petzl Corax

SizeWaistLeg loopWeight
125.5–37.7 in18.8–23.2 in470 g
229.9–42.1 in21.2–26.3 in520 g

Waist first, then the leg loops

Both ranges are circumferences: one around the waist where the belt sits, one around the thigh where the leg loop sits. A size fits when both measurements sit inside its ranges. Black Diamond's sizes mostly step three inches at the waist (27–30 in for a small, 30–33 in for a medium) and their leg ranges overlap, so the thigh often settles a borderline waist. Petzl's Corax covers more with fewer sizes: size 1 runs 25.5–37.7 in at the waist and size 2 29.9–42.1 in, so any waist between 29.9 and 37.7 in fits both and the 18.8–23.2 in versus 21.2–26.3 in leg loops decide.

REI's listing adds a buyer note for the Momentum: "Fits slightly large based on reviews.". That is a review comment rather than a brand figure, so the table above still reads the printed ranges. Women's harnesses use different ranges and are not covered here yet.

Related sizes

Climbing approaches are hikes: day-pack volume and trekking pole length. For the full profile, the profile tool takes a waist measurement. The guides explain how each brand's chart is read.

Try a harness on and hang in it before climbing; printed ranges are a starting point. Sources: methodology.