Shirt Size Converter

Shirt sizing carries two parallel conventions. Casual and knit shirts use ordinal letters, where each step of S, M, L and XL corresponds to roughly a 2 inch band of chest circumference: about 34 to 36 inches for men's XS, 38 to 40 for M, and 42 to 44 for XL. Continental European numbers are dimensional instead, set at approximately half the chest measurement in centimeters, which is why a 96 to 102 cm chest reads as EU 48 and lines up with a US Medium. Men's dress shirts use a third scheme entirely, the neck circumference in inches from about 14 to 18 in half-inch steps, usually paired with a sleeve length, because a collar must fit the neck precisely while the body does not. The number that matters is ease, the difference between the garment and the body. Slim cuts allow roughly 2 to 3 inches over the chest, classic cuts 3 to 5, and relaxed cuts 5 to 7, so two shirts sharing a label can differ by 4 inches of finished width. Asian domestic sizing is graded to smaller mean frames and typically runs one to two letters below Western equivalents. Because letter labels have drifted upward for decades through vanity sizing, a conversion table should be read as an approximation and confirmed against the flat garment measurements a retailer publishes.

Standard shirt sizing began with the collar rather than the body. In 1827, in Troy, New York, Hannah Lord Montague is credited with cutting the collar from her husband's shirt so it could be washed separately, and the detachable collar industry that grew around Troy made neck circumference in inches the first widely used shirt measurement, since only the collar had to fit exactly. Shirts of the period were otherwise cut generously and gathered, so body size mattered far less than it does now. Graded body sizing followed the same path as menswear generally: mass anthropometric data collected for military clothing during and after the American Civil War gave manufacturers the proportional tables needed to cut in quantity. Letter sizing, S through XL, spread in the twentieth century with knitwear, sweatshirts and the T-shirt, garments whose stretch made fine graduation unnecessary, and it eventually migrated onto woven shirts as well. Formal standardisation arrived later and is only partly binding in practice: ISO 8559 defines how body dimensions for garment construction are to be measured, ASTM International publishes body measurement tables used by many US manufacturers, and the European EN 13402 series introduced from 2004 labels garments by body dimensions in centimeters.