Under Armour to Gap clothing size
The short answer
Under Armour XS is Gap 2 by the two brands' own charts.
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 | Gap, by chart | Same label | Gap builds it for | Gap also prints |
|---|---|---|---|---|---|
| XXS | bust 31 to 32.5 in, waist 24.5 to 25.5 in | 00 or 0 | 000 | bust 31.3 in, waist 24.8 in, hip 34.3 in | Letter XXS |
| XS | bust 32.5 to 33.5 in, waist 25.5 to 27 in | 2 | not published | bust 33.3 in, waist 26.5 in, hip 36.3 in | Letter XS |
| SM | bust 33.5 to 36 in, waist 27 to 29 in | 4 or 6 | not published | bust 34.3 in, waist 27.5 in, hip 37.3 in | Letter S |
| MD | bust 36 to 38 in, waist 29 to 31 in | 10 | not published | bust 37.3 in, waist 30.5 in, hip 40.3 in | Letter M |
| LG | bust 38 to 41 in, waist 31 to 34 in | 12 or 14 | not published | bust 38.8 in, waist 32 in, hip 41.8 in | Letter L |
| XL | bust 41 to 44 in, waist 34 to 37 in | 16 | 16 | bust 42 in, waist 35.5 in, hip 45.3 in | Letter XL |
| XXL | bust 44 to 47 in, waist 37 to 40 in | 20 | 18 | bust 45.8 in, waist 39.5 in, hip 49.3 in | Letter XXL |
| 3XL | bust 47 to 50 in, waist 40 to 43 in | 22 | 20 | bust 47.8 in, waist 41.5 in, hip 51.3 in | Letter XXL |
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
- Gap size guide, read on 2026-09-18. Gap on TrueToSize