SIZE M SHIRTS

Manufacturers tightened their templates steadily from the 1990s into the 2010s, and the middle of the size range shows that shift most clearly, since a boxier older cut and a slimmer modern one both get labeled M despite fitting very differently. A Diadora Italy shirt from 1994 and a Pogba Juventus third shirt from 2015-16 sit at opposite ends of that same letter, two decades of the same size drifting apart under the same three brands, Adidas, Nike and Kappa, that shaped most of the shirts on this page. Brand and country of manufacture add further variation on top of the decade itself, which is why a label alone was never going to be reliable across a range this wide.

Every shirt here carries its own flat pit-to-pit and top-to-bottom measurement rather than relying on the tag, so it is worth checking those numbers against a shirt you already own that fits well, instead of assuming a labeled M matches what you'd expect from a current retail size chart. That check matters most on anything from before 2005, when the gap between a boxy M and a slim one was at its widest.