Drop, stack height and weight: what running shoe numbers mean

Stack height

Stack height is how much material sits under your foot, measured at the heel and at the forefoot. More stack usually means more cushioning between you and the ground.

• Road shoes: heel stack from 27 to 46 mm, median 37.5 mm. 43 of 71 sit between 35 and 40 mm, and 16 are 40 mm or more.
• Trail shoes: 23.3 to 44 mm, median 36.9 mm. Technical-terrain trail shoes run lowest, with a median of 29 mm.
• Max-cushion road shoes have a median heel stack of 41.8 mm; carbon-plate racers, 38.1 mm. A racing shoe isn't a thin shoe any more.

Heel-to-toe drop

Drop is the heel stack minus the forefoot stack. It says how much higher your heel sits than your toes, not how much cushion there is: a shoe can be thick and still have zero drop.

• Road shoes: 0 to 12 mm. 8 mm is the most common drop (28 of 70 road shoes with a listed drop), and 53 of 70 fall between 4.5 and 8 mm.
• Trail shoes run a little lower: median 6.7 mm.
• Zero drop is rare: one road shoe (Altra Torin 9) and one trail shoe (Altra Lone Peak 9+).

If you change drop by several millimetres from what you're used to, the shoe will feel different.

Weight

Most makers list a weight for one reference size, and the size they use varies, so compare weights between shoes rather than reading them exactly.

• Road shoes, men's: 5.1 to 12.5 oz, median 9.3 oz. Women's median: 7.9 oz.
• Trail shoes, men's: 8.1 to 11.9 oz, median 10.1 oz. Women's median: 8.7 oz.
• Stability road shoes are the heaviest group (median 10.6 oz, men's); carbon-plate racers the lightest (6.8 oz).

How our finder uses these numbers

• It doesn't score drop or stack height.
• It counts weight only if you tell it you want a lighter shoe, and then as a small factor beside fit, the kind of shoe and cushioning.
• To see every current shoe's numbers side by side: road running shoes and trail running shoes.