The finished row is more useful than the size name
Dior publishes garment measurements for some ready-to-wear pieces against each size, including shoulder, chest and length. The row is more informative than a conversion chart because it records the object that will arrive. For the Oblique relaxed-fit hooded sweatshirt, the length steps from 61.5 cm at 3XS to 68.5 cm at 3XL, a spread of 7 cm, while the chest rises 36 cm. The same label therefore changes far more in width than in vertical coverage. Compare those two rates before treating a larger size as a solution for short sleeves or a longer body.
French letters are not Italian numbers
Dior's women's ready-to-wear uses French sizing while its men's pieces often use letters; the exact product page should be the source of truth. An FR 38 on a women's garment is not the same body as an Italian 38. On men's pages, a letter such as M can be paired with regional conversion columns or the model's wearing size. Write down the system printed by Dior for the exact piece rather than carrying a conversion from another house. The label is stable; the translated number is not.
Knit and fleece do different things after wear
A fine-gauge knit can hold a crisp shoulder line but offer less stretch, while cotton fleece is softer through the body and ribbed at the cuffs and hem. Fleece can relax with wear and washing, making a close garment feel easier without changing the shoulder seam. A dense wool knit may mark a tight chest sooner because the fabric has less give. Care wording matters for the final fit: dry cleaning, hand washing and machine washing can all alter the surface differently. The composition should be read before deciding that a garment will stretch to fit.
Five numbers for a Dior sweater
Measure a sweater you like at the underarms and double it, then record shoulder seam width, centre-back length, sleeve length and unstretched hem width. Add the Dior fit word and the marked size. For a textured knit, measure the chest in two places and avoid pulling a single loose edge. For fleece, flatten the rib without stretching it. The same method makes a roomy sweater comparable with a close one. If the chest matches but the sleeve is 3 cm shorter, the fit difference is not your torso; the next size may add the sleeve while changing the body more than desired.
The practical answer for a roomy knit
A roomy Dior sweater should still place the shoulder seam where the sleeve can hang without pulling. Chest ease can be intentional, but a shoulder that sits well beyond the natural point changes how the sleeve behaves. Check the unstretched hem before accepting a wide body, because a strong rib can gather the garment upward. If the intended look is clean and relaxed, choose the row whose shoulder and length already match; if the look is deliberately oversized, compare the finished chest with a sweater you like rather than assuming that the word relaxed supplies a fixed number.