Gymshark to Under Armour leggings size

The short answer

Gymshark S is Under Armour SM by the two brands' own charts. 5 of 7 Gymshark sizes land on a different label at Under Armour.

Both brands publish the body waist each size is cut for, so every row matches a waist, not a tag.

Every Gymshark size read across to Under Armour. Letter sizes on the left, Letter on the right.
Gymshark	Gymshark builds it for	Under Armour, by chart	Same label	Under Armour builds it for	Under Armour also prints
XXS	waist 24 in, hip 35.5 in	XXS	XXS	waist 24.5 to 25.5 in, hip 33 to 34.5 in	US numeric 00
XS	waist 26 in, hip 37.5 in	XS	XS	waist 25.5 to 27 in, hip 34.5 to 36 in	US numeric 0-2
S	waist 28 in, hip 39.5 in	SM	not published	waist 27 to 29 in, hip 36 to 38 in	US numeric 4-6
M	waist 30 in, hip 41.5 in	MD	not published	waist 29 to 31 in, hip 38 to 40 in	US numeric 8-10
L	waist 32 in, hip 43.5 in	LG	not published	waist 31 to 34 in, hip 40 to 43 in	US numeric 12-14
XL	waist 34 in, hip 45.5 in	LG	XL	waist 31 to 34 in, hip 40 to 43 in	US numeric 12-14
XXL	waist 36 in, hip 47.7 in	XL	XXL	waist 34 to 37 in, hip 43 to 46 in	US numeric 16

Tinted rows change label or sit between two sizes. Read from the two charts only; no formula and no averaging.

What wearers say

Charts describe a garment. People who own both brands describe a fit, and their answer ranks above this table once five of them stand behind it. Pick your size in the converter to see whether there are enough yet.

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Sources

Gymshark size guide, read on 2026-09-17. Gymshark on TrueToSize
Under Armour size guide, read on 2026-09-17. Under Armour on TrueToSize

Under Armour to Gymshark