The length of men's duffle coat has changed over the course of the 20th century. The first duffle coats, produced at the turn of the XIX and XX centuries, were quite short — their length was approximately equal to the length of the pea coat. During the Second World War, the length was increased, and duffle coats began to reach the knees. In the second half of XX century, when these coats have gained wide popularity among the civilians, there were other market options for length.
We recommend you to buy a duffle coat of the length that seems to you the most convenient. Do not think that the medium length models are too fashionable or obviously youthful — in fact, they are suitable for many men. However, it should be noted that the longest models usually look the most authentic... However, the choice of clothing is unlikely to be the first to strive for maximum authenticity.