Gymshark to Gap size
The short answer
Gymshark XS is Gap S by the two brands' own charts. 4 of 7 Gymshark sizes land on a different label at Gap.
Both brands publish the body chest each size is cut for, so every row matches a chest, not a letter.
| Gymshark | Gymshark builds it for | Gap, by chart | Same label | Gap builds it for | Gap also prints |
|---|---|---|---|---|---|
| XS | chest 37 in, waist 29.5 in | S | XS | chest 37 to 38 in, neck 14 to 14.5 in, sleeve 32 to 33 in | not published |
| S | chest 39 in, waist 31.5 in | M | S | chest 39 to 41 in, neck 15 to 15.5 in, sleeve 33 to 34 in | not published |
| M | chest 41 in, waist 33.5 in | M | M | chest 39 to 41 in, neck 15 to 15.5 in, sleeve 33 to 34 in | not published |
| L | chest 43 in, waist 35.5 in | L | L | chest 42 to 44 in, neck 16 to 16.5 in, sleeve 34 to 35 in | not published |
| XL | chest 45 in, waist 37.5 in | XL | XL | chest 45 to 48 in, neck 17 to 17.5 in, sleeve 35 to 35.5 in | not published |
| XXL | chest 47 in, waist 39.5 in | XL | XXL | chest 45 to 48 in, neck 17 to 17.5 in, sleeve 35 to 35.5 in | not published |
| XXXL | chest 49 in, waist 41.5 in | XXL | XXXL | chest 49 to 52 in, neck 18 to 18.5 in, sleeve 35.5 to 36 in | 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
- Gymshark size guide, read on 2026-09-18. Gymshark on TrueToSize
- Gap size guide, read on 2026-09-18. Gap on TrueToSize