Gymshark to Marks & Spencer size
The short answer
Gymshark XS is Marks & Spencer S by the two brands' own charts. 4 of 7 Gymshark sizes land on a different label at Marks & Spencer.
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 | Marks & Spencer, by chart | Same label | Marks & Spencer builds it for | Marks & Spencer also prints |
|---|---|---|---|---|---|
| XS | chest 37 in, waist 29.5 in | S | XS | chest 35 to 37 in | not published |
| S | chest 39 in, waist 31.5 in | M | S | chest 38 to 40 in | not published |
| M | chest 41 in, waist 33.5 in | L | M | chest 41 to 43 in | not published |
| L | chest 43 in, waist 35.5 in | L | L | chest 41 to 43 in | not published |
| XL | chest 45 in, waist 37.5 in | XL | XL | chest 44 to 46 in | not published |
| XXL | chest 47 in, waist 39.5 in | XXL | XXL | chest 47 to 49 in | not published |
| XXXL | chest 49 in, waist 41.5 in | XXL | XXXL | chest 47 to 49 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
- Marks & Spencer size guide, read on 2026-09-18.