Under Armour to GU clothing size
The short answer
Under Armour XXS is GU M by the two brands' own charts. 7 of 7 Under Armour sizes land on a different label at GU.
Both brands publish the body bust each size is cut for, so every row matches a bust, not a letter or a number.
On 2 sizes the charts land two or more sizes from the same label. Brands do not measure the body the same way, so on those rows treat the chart answer and the same label as the two ends of a range.
| Under Armour | Under Armour builds it for | GU Japan sizing, by chart | Same label | GU builds it for | GU also prints |
|---|---|---|---|---|---|
| XXS | bust 31 to 32.5 in, waist 24.5 to 25.5 in | M | not published | bust 31.5 to 33.5 in, waist 24.8 to 26.4 in, hip 33.5 to 35 in | not published |
| XS | bust 32.5 to 33.5 in, waist 25.5 to 27 in | M | XS | bust 31.5 to 33.5 in, waist 24.8 to 26.4 in, hip 33.5 to 35 in | not published |
| SM | bust 33.5 to 36 in, waist 27 to 29 in | L | not published | bust 33.5 to 35.4 in, waist 26.4 to 28 in, hip 35 to 36.6 in | not published |
| MD | bust 36 to 38 in, waist 29 to 31 in | XL | not published | bust 35.4 to 37.8 in, waist 28 to 30.3 in, hip 36.6 to 38.6 in | not published |
| LG | bust 38 to 41 in, waist 31 to 34 in | XXL | not published | bust 37.8 to 40.2 in, waist 30.3 to 32.7 in, hip 38.6 to 40.6 in | not published |
| XL | bust 41 to 44 in, waist 34 to 37 in | 3XL | XL | bust 40.2 to 43.3 in, waist 32.7 to 35.4 in, hip 40.6 to 43.3 in | not published |
| XXL | bust 44 to 47 in, waist 37 to 40 in | 3XL | XXL | bust 40.2 to 43.3 in, waist 32.7 to 35.4 in, hip 40.6 to 43.3 in | not published |
| 3XL | bust 47 to 50 in, waist 40 to 43 in | not made | 3XL | not published | 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
- GU Japan sizing size guide, read on 2026-09-25.