J.Crew to Under Armour size
The short answer
J.Crew S is Under Armour SM by the two brands' own charts. 5 of 7 J.Crew 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.
| J.Crew | J.Crew builds it for | Under Armour, by chart | Same label | Under Armour builds it for | Under Armour also prints |
|---|---|---|---|---|---|
| XS | chest 32 to 34 in, waist 26 to 28 in, neck 13 to 13.5 in, sleeve 31 to 32 in | XS | XS | chest 31 to 34 in, waist 28 to 29 in | not published |
| S | chest 35 to 37 in, waist 29 to 31 in, neck 14 to 14.5 in, sleeve 32 to 33 in | SM | not published | chest 34 to 37 in, waist 29 to 31 in | not published |
| M | chest 38 to 40 in, waist 32 to 34 in, neck 15 to 15.5 in, sleeve 33 to 34 in | MD | not published | chest 37 to 41 in, waist 31 to 34 in | not published |
| L | chest 41 to 43 in, waist 35 to 37 in, neck 16 to 16.5 in, sleeve 34 to 35 in | LG | not published | chest 41 to 44 in, waist 34 to 37 in | not published |
| XL | chest 44 to 46 in, waist 38 to 40 in, neck 17 to 17.5 in, sleeve 35 to 36 in | XL | XL | chest 44 to 48 in, waist 37 to 41 in | not published |
| XXL | chest 47 to 49 in, waist 41 to 43 in, neck 18 to 18.5 in, sleeve 36 to 37 in | XL | XXL | chest 44 to 48 in, waist 37 to 41 in | not published |
| XXXL | chest 50 to 52 in, waist 44 to 45 in, neck 18 to 18.5 in, sleeve 36 to 37 in | XXL | 3XL | 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
- J.Crew size guide, read on 2026-09-18.
- Under Armour size guide, read on 2026-09-18. Under Armour on TrueToSize