Under Armour to Whistles clothing size
The short answer
Under Armour MD is Whistles 12 or 14 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 | Whistles, by chart | Same label | Whistles builds it for | Whistles also prints |
|---|---|---|---|---|---|
| XXS | bust 31 to 32.5 in, waist 24.5 to 25.5 in | 08 | not published | bust 32 in, waist 25.5 in, hip 36.5 in | not published |
| XS | bust 32.5 to 33.5 in, waist 25.5 to 27 in | 08 or 10 | not published | bust 32 in, waist 25.5 in, hip 36.5 in | not published |
| SM | bust 33.5 to 36 in, waist 27 to 29 in | 10 or 12 | not published | bust 34 in, waist 27.5 in, hip 38.5 in | not published |
| MD | bust 36 to 38 in, waist 29 to 31 in | 12 or 14 | not published | bust 36 in, waist 29.5 in, hip 40.5 in | not published |
| LG | bust 38 to 41 in, waist 31 to 34 in | 16 | not published | bust 40 in, waist 33.5 in, hip 44.5 in | not published |
| XL | bust 41 to 44 in, waist 34 to 37 in | 18 | not published | bust 42.5 in, waist 35.5 in, hip 46.5 in | not published |
| XXL | bust 44 to 47 in, waist 37 to 40 in | 20 | not published | bust 45 in, waist 38 in, hip 49 in | not published |
| 3XL | bust 47 to 50 in, waist 40 to 43 in | not made | not published | 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
- Whistles size guide, read on 2026-09-18.