Gap to MUJI size
The short answer
Gap XS is MUJI M by the two brands' own charts. 5 of 5 Gap sizes land on a different label at MUJI.
Both brands publish the body chest each size is cut for, so every row matches a chest, not a letter.
On 1 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.
| Gap | Gap builds it for | MUJI Japan sizing, by chart | Same label | MUJI builds it for | MUJI also prints |
|---|---|---|---|---|---|
| XS | chest 35 to 36 in, neck 13.5 to 14 in, sleeve 31 to 32 in | M | XS | chest 34.7 to 37.8 in, waist 29.9 to 33.1 in, hip 35.4 to 38.6 in | not published |
| S | chest 37 to 38 in, neck 14 to 14.5 in, sleeve 32 to 33 in | M | S | chest 34.7 to 37.8 in, waist 29.9 to 33.1 in, hip 35.4 to 38.6 in | not published |
| M | chest 39 to 41 in, neck 15 to 15.5 in, sleeve 33 to 34 in | L | M | chest 37.8 to 40.9 in, waist 33.1 to 36.2 in, hip 38.6 to 41.7 in | not published |
| L | chest 42 to 44 in, neck 16 to 16.5 in, sleeve 34 to 35 in | XL | L | chest 40.9 to 44.1 in, waist 36.2 to 39.4 in, hip 41.7 to 44.9 in | not published |
| XL | chest 45 to 48 in, neck 17 to 17.5 in, sleeve 35 to 35.5 in | XXL | XL | chest 44.1 to 47.2 in, waist 39.4 to 42.5 in, hip 44.9 to 48 in | not published |
| XXL | chest 49 to 52 in, neck 18 to 18.5 in, sleeve 35.5 to 36 in | not made | XXL | not published | not published |
| XXXL | chest 55 in, neck 18.8 in, sleeve 36.5 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
- Gap size guide, read on 2026-09-18. Gap on TrueToSize
- MUJI Japan sizing size guide, read on 2026-09-25.