Lululemon to Under Armour clothing size
The short answer
lululemon XS is Under Armour XXS by the two brands' own charts. 7 of 7 lululemon sizes land on a different label at Under Armour.
Both brands publish the body bust each size is cut for, so every row matches a bust, not a letter or a number.
| lululemon | lululemon builds it for | Under Armour, by chart | Same label | Under Armour builds it for | Under Armour also prints |
|---|---|---|---|---|---|
| XXXS | bust 28.5 in | not made | not published | not published | not published |
| XXS | bust 30 in | not made | XXS | not published | not published |
| XS | bust 31 to 32 in | XXS | XS | bust 31 to 32.5 in, waist 24.5 to 25.5 in | US 00 |
| S | bust 33 to 34 in | XS | not published | bust 32.5 to 33.5 in, waist 25.5 to 27 in | US 0-2 |
| M | bust 35 to 36 in | SM | not published | bust 33.5 to 36 in, waist 27 to 29 in | US 4-6 |
| L | bust 37 to 38.5 in | MD | not published | bust 36 to 38 in, waist 29 to 31 in | US 8-10 |
| XL | bust 40 to 42 in | LG | XL | bust 38 to 41 in, waist 31 to 34 in | US 12-14 |
| 1X | bust 45 to 47 in | XXL | not published | bust 44 to 47 in, waist 37 to 40 in | US 18 |
| 2X | bust 49 to 51 in | 3XL | not published | bust 47 to 50 in, waist 40 to 43 in | US 20 |
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
- lululemon size guide, read on 2026-09-18. lululemon on TrueToSize
- Under Armour size guide, read on 2026-09-18. Under Armour on TrueToSize