SET Active to Under Armour leggings size

The short answer

SET Active XS is Under Armour XXS by the two brands' own charts. 4 of 6 SET Active 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 SET Active size read across to Under Armour. Letter sizes on the left, Letter on the right.
SET Active	SET Active builds it for	Under Armour, by chart	Same label	Under Armour builds it for	Under Armour also prints
XS	waist 22 to 24 in	XXS	XS	waist 24.5 to 25.5 in, hip 33 to 34.5 in	US numeric 00
S	waist 25 to 27 in	XS	not published	waist 25.5 to 27 in, hip 34.5 to 36 in	US numeric 0-2
M	waist 28 to 30 in	SM	not published	waist 27 to 29 in, hip 36 to 38 in	US numeric 4-6
L	waist 31 to 33 in	LG	not published	waist 31 to 34 in, hip 40 to 43 in	US numeric 12-14
XL	waist 34 to 36 in	XL	XL	waist 34 to 37 in, hip 43 to 46 in	US numeric 16
XXL	waist 37 to 40 in	XXL	XXL	waist 37 to 40 in, hip 46 to 49 in	US numeric 18

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

SET Active size guide, read on 2026-09-18.
Under Armour size guide, read on 2026-09-17. Under Armour on TrueToSize

Under Armour to SET Active