Reformation to GU clothing size
The short answer
Reformation XS is GU M by the two brands' own charts. 5 of 5 Reformation sizes land on a different label at GU.
Both brands publish the body bust each size is cut for, so every row matches a bust, not a letter or a number.
On 5 sizes the charts land two or more sizes from the same label. Brands do not measure the body the same way, so on those rows treat the chart answer and the same label as the two ends of a range.
| Reformation | Reformation builds it for | GU Japan sizing, by chart | Same label | GU builds it for | GU also prints |
|---|---|---|---|---|---|
| XS | bust 33 in, waist 25 in, hip 36 in | M | XS | bust 31.5 to 33.5 in, waist 24.8 to 26.4 in, hip 33.5 to 35 in | not published |
| S | bust 35 in, waist 27 in, hip 38 in | L | S | bust 33.5 to 35.4 in, waist 26.4 to 28 in, hip 35 to 36.6 in | not published |
| M | bust 37 in, waist 29 in, hip 40 in | XL | M | bust 35.4 to 37.8 in, waist 28 to 30.3 in, hip 36.6 to 38.6 in | not published |
| L | bust 39.5 in, waist 31.5 in, hip 42.5 in | XXL | L | bust 37.8 to 40.2 in, waist 30.3 to 32.7 in, hip 38.6 to 40.6 in | not published |
| XL | bust 41.5 in, waist 33.5 in, hip 44.5 in | 3XL | XL | bust 40.2 to 43.3 in, waist 32.7 to 35.4 in, hip 40.6 to 43.3 in | not published |
| 1X | bust 45 in, waist 37.5 in, hip 47.5 in | not made | not published | not published | not published |
| 2X | bust 48 in, waist 40.5 in, hip 50.5 in | not made | not published | not published | not published |
| 3X | bust 51 in, waist 43.5 in, hip 53.5 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
- Reformation size guide, read on 2026-09-18. Reformation on TrueToSize
- GU Japan sizing size guide, read on 2026-09-25.