Under Armour to Lacoste size
The short answer
Under Armour SM is Lacoste S by the two brands' own charts. 6 of 8 Under Armour sizes land on a different label at Lacoste.
Both brands publish the body chest each size is cut for, so every row matches a chest, not a letter.
| Under Armour | Under Armour builds it for | Lacoste, by chart | Same label | Lacoste builds it for | Lacoste also prints |
|---|---|---|---|---|---|
| XS | chest 31 to 34 in, waist 28 to 29 in | XS | XS | chest 34 in, waist 28 in | not published |
| SM | chest 34 to 37 in, waist 29 to 31 in | S | not published | chest 35 to 37 in, waist 30 to 31 in | not published |
| MD | chest 37 to 41 in, waist 31 to 34 in | M | not published | chest 38 to 40 in, waist 33 to 35 in | not published |
| LG | chest 41 to 44 in, waist 34 to 37 in | L | not published | chest 41 to 43 in, waist 36 to 38 in | not published |
| XL | chest 44 to 48 in, waist 37 to 41 in | XL | XL | chest 44 to 46 in, waist 39 to 42 in | not published |
| XXL | chest 48 to 52 in, waist 41 to 45.5 in | 3XL or 2XL | 2XL | chest 51 in, waist 48 in | not published |
| 3XL | chest 52 to 56 in, waist 45.5 to 50 in | 4X or 1XG | 3XL | chest 53 in, waist 50 in | not published |
| 4XL | chest 56 to 60 in, waist 50 to 54.5 in | 2XG | not published | chest 57 in, waist 54 in | not published |
| 5XL | chest 60 to 64 in, waist 54.5 to 59 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
- Lacoste size guide, read on 2026-09-18.