If you do not know what size mailbox you currently have, an easy way to find out is to look at the hinge that connects your door to your mailbox. If you see three screws across the top and bottom, with a total of six screws on your hinge, you have a standard sized box!

An estate box is much larger than an Imperial standard sized box. To identify if you have an estate box. You can look at your current box and look at the hinge connecting the door to the box. If you see four screws across the top and bottom, with a total of eight screws, you have an estate-sized mailbox!