US jackets sizing system (Medium Regular etc.)

Most modern civilian sizing systems ignore the fact that people come not only in different widths, but in different lengths too. US Army sizing system incorporates both dimensions in a very simple way. The sizes should sound familiar, but beware: civilian S, M, L etc are a completely different thing. US Army X-Large is really pretty effin' large, way bigger than normal civilian XL.

Because of the two different measurements, us sizes have two parts. For an example Medium Regular is Medium in width and Regular in height. Surprisingly, this is the average male size! Medium Long would be exactly the same width but with longer sleeves and hem. Large Regular would be same length as Medium Regular but more roomy on the chest. Most new items come only in regular lengths, because most people fit regular and the manufacturers want to cut costs. We'd like to sell longs and shorts, but what can you do if nobody makes them.

Jackets sizing is a little more forgiving than trousers sizing. If you are very tall, you can take one or more wider. This moves the shoulder seams towards the arms and the end result is that the sleeves cover more arms. The negative is that the jacket will be way too roomy on the waist.

Length

Length sizing can give a little, for an example Regular passes for 183 cm tall person, at least sort of.

Widths