Under Armour to Arc'teryx clothing size
The short answer
Under Armour XXS is Arc'teryx XS by the two brands' own charts. 6 of 8 Under Armour sizes land on a different label at Arc'teryx.
Both brands publish the body bust each size is cut for, so every row matches a bust, not a letter or a number.
| Under Armour | Under Armour builds it for | Arc'teryx, by chart | Same label | Arc'teryx builds it for | Arc'teryx also prints |
|---|---|---|---|---|---|
| XXS | bust 31 to 32.5 in, waist 24.5 to 25.5 in | XS | not published | bust 33.1 in, waist 26.8 in, hip 36.2 in | not published |
| XS | bust 32.5 to 33.5 in, waist 25.5 to 27 in | XS | XS | bust 33.1 in, waist 26.8 in, hip 36.2 in | not published |
| SM | bust 33.5 to 36 in, waist 27 to 29 in | S | not published | bust 35 in, waist 28.7 in, hip 38.2 in | not published |
| MD | bust 36 to 38 in, waist 29 to 31 in | M | not published | bust 37 in, waist 30.7 in, hip 40.2 in | not published |
| LG | bust 38 to 41 in, waist 31 to 34 in | L | not published | bust 40.2 in, waist 33.9 in, hip 43.3 in | not published |
| XL | bust 41 to 44 in, waist 34 to 37 in | XL or L | XL | bust 44.1 in, waist 37.8 in, hip 47.2 in | not published |
| XXL | bust 44 to 47 in, waist 37 to 40 in | XL or XXL | XXL | bust 44.1 in, waist 37.8 in, hip 47.2 in | not published |
| 3XL | bust 47 to 50 in, waist 40 to 43 in | XXL | not published | bust 48 in, waist 41.7 in, hip 51.2 in | not published |
What wearers say
Charts describe a garment, not a fit. We do not collect fit reports for this category yet, so this table is the two brands' own claims and nothing more.
Sources
- Under Armour size guide, read on 2026-09-18. Under Armour on TrueToSize
- Arc'teryx size guide, read on 2026-09-18.