Champion to Under Armour size
The short answer
Champion S is Under Armour SM by the two brands' own charts. 4 of 6 Champion sizes land on a different label at Under Armour.
Both brands publish the body chest each size is cut for, so every row matches a chest, not a letter.
| Champion | Champion builds it for | Under Armour, by chart | Same label | Under Armour builds it for | Under Armour also prints |
|---|---|---|---|---|---|
| XS | chest 32 to 36 in, waist 28 to 30 in | XS | XS | chest 31 to 34 in, waist 28 to 29 in | not published |
| S | chest 36 to 38 in, waist 30 to 32 in | SM | not published | chest 34 to 37 in, waist 29 to 31 in | not published |
| M | chest 38 to 41 in, waist 32 to 35 in | MD | not published | chest 37 to 41 in, waist 31 to 34 in | not published |
| L | chest 41 to 45 in, waist 35 to 39 in | LG | not published | chest 41 to 44 in, waist 34 to 37 in | not published |
| XL | chest 45 to 49 in, waist 39 to 44 in | XL | XL | chest 44 to 48 in, waist 37 to 41 in | not published |
| 2XL | chest 49 to 53 in, waist 44 to 48 in | XXL | XXL | chest 48 to 52 in, waist 41 to 45.5 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
- Champion size guide, read on 2026-09-18.
- Under Armour size guide, read on 2026-09-18. Under Armour on TrueToSize