Nike to Under Armour size
The short answer
Nike XXS is Under Armour XS by the two brands' own charts. 5 of 9 Nike 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.
| Nike | Nike builds it for | Under Armour, by chart | Same label | Under Armour builds it for | Under Armour also prints |
|---|---|---|---|---|---|
| XXS | chest 28.1 to 31.5 in, waist 22.5 to 25.5 in, hip 28.5 to 31.5 in | XS | not published | chest 31 to 34 in, waist 28 to 29 in | not published |
| XS | chest 31.5 to 35 in, waist 25.5 to 29 in, hip 31.5 to 35 in | XS | XS | chest 31 to 34 in, waist 28 to 29 in | not published |
| S | chest 35 to 37.5 in, waist 29 to 32 in, hip 35 to 37.5 in | SM | not published | chest 34 to 37 in, waist 29 to 31 in | not published |
| M | chest 37.5 to 41 in, waist 32 to 35 in, hip 37.5 to 41 in | MD | not published | chest 37 to 41 in, waist 31 to 34 in | not published |
| L | chest 41 to 44 in, waist 35 to 38 in, hip 41 to 44 in | LG | not published | chest 41 to 44 in, waist 34 to 37 in | not published |
| XL | chest 44 to 48.5 in, waist 38 to 43 in, hip 44 to 47 in | XL | XL | chest 44 to 48 in, waist 37 to 41 in | not published |
| XXL | chest 48.5 to 53.5 in, waist 43 to 47.5 in, hip 47 to 50.5 in | XXL | XXL | chest 48 to 52 in, waist 41 to 45.5 in | not published |
| 3XL | chest 53.5 to 58 in, waist 47.5 to 52.5 in, hip 50.5 to 53.5 in | 3XL | 3XL | chest 52 to 56 in, waist 45.5 to 50 in | not published |
| 4XL | chest 58 to 63 in, waist 52.5 to 57 in, hip 53.5 to 58.5 in | 5XL | 4XL | chest 60 to 64 in, waist 54.5 to 59 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
- Nike size guide, read on 2026-09-18. Nike on TrueToSize
- Under Armour size guide, read on 2026-09-18. Under Armour on TrueToSize