Under Armour to Reformation clothing size
The short answer
Under Armour XXS is Reformation XS by the two brands' own charts. 6 of 8 Under Armour sizes land on a different label at Reformation.
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 | Reformation, by chart | Same label | Reformation builds it for | Reformation also prints |
|---|---|---|---|---|---|
| XXS | bust 31 to 32.5 in, waist 24.5 to 25.5 in | XS | not published | bust 33 in, waist 25 in, hip 36 in | US 0 |
| XS | bust 32.5 to 33.5 in, waist 25.5 to 27 in | XS | XS | bust 33 in, waist 25 in, hip 36 in | US 0 |
| SM | bust 33.5 to 36 in, waist 27 to 29 in | S | not published | bust 35 in, waist 27 in, hip 38 in | US 2/4 |
| MD | bust 36 to 38 in, waist 29 to 31 in | M | not published | bust 37 in, waist 29 in, hip 40 in | US 6/8 |
| LG | bust 38 to 41 in, waist 31 to 34 in | L | not published | bust 39.5 in, waist 31.5 in, hip 42.5 in | US 10 |
| XL | bust 41 to 44 in, waist 34 to 37 in | XL | XL | bust 41.5 in, waist 33.5 in, hip 44.5 in | US 12 |
| XXL | bust 44 to 47 in, waist 37 to 40 in | 1X | not published | bust 45 in, waist 37.5 in, hip 47.5 in | US 14 |
| 3XL | bust 47 to 50 in, waist 40 to 43 in | 2X | not published | bust 48 in, waist 40.5 in, hip 50.5 in | US 16/18 |
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
- Reformation size guide, read on 2026-09-18. Reformation on TrueToSize