Under Armour to J.Crew clothing size
The short answer
Under Armour XS is J.Crew 0 by the two brands' own charts.
Both brands publish the body bust each size is cut for, so every row matches a bust, not a letter or a number.
| Under Armour | Under Armour builds it for | J.Crew, by chart | Same label | J.Crew builds it for | J.Crew also prints |
|---|---|---|---|---|---|
| XXS | bust 31 to 32.5 in, waist 24.5 to 25.5 in | 00 | 000 | bust 32 in, waist 24 in | Letter XXS · UK 2 · DE 26 · FR 30 · IT 34 · AU 2 · JP 1 |
| XS | bust 32.5 to 33.5 in, waist 25.5 to 27 in | 0 | not published | bust 33 in, waist 25 in | Letter XS · UK 4 · DE 28 · FR 32 · IT 36 · AU 4 · JP 3 |
| SM | bust 33.5 to 36 in, waist 27 to 29 in | 4 | not published | bust 35 in, waist 27 in | Letter S · UK 8 · DE 34 · FR 36 · IT 40 · AU 8 · JP 7 |
| MD | bust 36 to 38 in, waist 29 to 31 in | 8 | not published | bust 37 in, waist 29 in | Letter M · UK 12 · DE 36 · FR 40 · IT 44 · AU 12 · JP 11 |
| LG | bust 38 to 41 in, waist 31 to 34 in | 12 | not published | bust 39.5 in, waist 31.5 in | Letter L · UK 16 · DE 40 · FR 44 · IT 48 · AU 16 · JP 15 |
| XL | bust 41 to 44 in, waist 34 to 37 in | 16 or 14 | 16 | bust 43.5 in, waist 35.5 in | Letter XL · UK 20 · DE 44 · FR 48 · IT 52 · AU 20 · JP 19 |
| XXL | bust 44 to 47 in, waist 37 to 40 in | 18 | 18 | bust 46 in, waist 38 in | Letter XXL / 1X · UK 22 · DE 46 · FR 50 · IT 54 · AU 22 · JP 21 |
| 3XL | bust 47 to 50 in, waist 40 to 43 in | 20 | 20 | bust 48.5 in, waist 40.5 in | Letter 2X · UK 24 · DE 48 · FR 52 · IT 56 · AU 24 · JP 23 |
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
- J.Crew size guide, read on 2026-09-18.