What is the most popular Birkin size?

Opinions vary about which Birkin size is the most popular. In general, the Birkin is the most well-known of all Hermès bags. It comes in 25-inch, 30-inch, 35-inch and 40-inch sizes. However, the smaller bags are often difficult to find. You'll find a variety of Hermès Birkin bags on 1stDibs.