Marks & Spencer to GU size
The short answer
Marks & Spencer XS is GU S by the two brands' own charts. 7 of 7 Marks & Spencer sizes land on a different label at GU.
Both brands publish the body chest each size is cut for, so every row matches a chest, not a letter.
| Marks & Spencer | Marks & Spencer builds it for | GU Japan sizing, by chart | Same label | GU builds it for | GU also prints |
|---|---|---|---|---|---|
| XS | chest 32 to 34 in | S | XS | chest 31.5 to 34.7 in, waist 26.8 to 29.9 in | not published |
| S | chest 35 to 37 in | M | S | chest 34.7 to 37.8 in, waist 29.9 to 33.1 in | not published |
| M | chest 38 to 40 in | L | M | chest 37.8 to 40.9 in, waist 33.1 to 36.2 in | not published |
| L | chest 41 to 43 in | XL | L | chest 40.9 to 44.1 in, waist 36.2 to 39.4 in | not published |
| XL | chest 44 to 46 in | XXL | XL | chest 44.1 to 47.2 in, waist 39.4 to 42.5 in | not published |
| XXL | chest 47 to 49 in | 3XL | XXL | chest 47.2 to 50.4 in, waist 42.5 to 45.7 in | not published |
| XXXL | chest 50 to 52 in | 3XL | 3XL | chest 47.2 to 50.4 in, waist 42.5 to 45.7 in | not published |
| 4XL | chest 52 to 54 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
- Marks & Spencer size guide, read on 2026-09-18.
- GU Japan sizing size guide, read on 2026-09-25.