Photo: Nancy Andrews
There are standard sizes recommended for mailboxes on most delivery routes, ranging from 19 to 23.5 inches long, 6.5 to 11.5 inches wide, and 8.5 to 13.5 inches high. If you build your own box, it can fall anywhere in this range, but you need to get the local postmaster's stamp of approval before it can become your official mailbox.