We get this question a lot!
The good news is that measuring your mailbox is pretty easy. The Postal Service has regulated the size and dimensions for traditional mailboxes for over 60 years now, making a universal door replacement possible regardless of the manufacturer.
The most consistent way to measure your mailbox is to measure the canister opening itself, not your old door. This is because USPS regulations dictate the opening size, not the door itself. This leaves some latitude, albeit minor, in the height of the actual doors across manufacturers which we will ignore.
To measure the width you want to place your tape measure on the outside of the canister of one side and measure outside to outside like the picture shows. For your height you want to go from the top of the arch to the bottom of the actual mailbox (where the bottom of the hinges are). Placing the tape measure on the floor of the mailbox will usually give you a smaller height by approximately 1/4".
Metal mailbox have a lip around the front opening of the mailbox where manufacturers curl the metal to remove sharp edges and to provide structural integrity. The RetroFit snaps into place behind this lip, securely holding the door in place. By measuring outside to outside, we are able to correctly size the opening without considering these ridges.
Most plastic mailboxes do not have lip at the front which prevents the RetroFit from snapping in place. This can be confusing as plastic mailboxes often times have similar size measurements to metal mailboxes. Unfortunately the RetroFit will not fit securely in place without that lip to snap behind.
Once you have your width and height measurements, you should be able to select one of the three standard USPS mailbox sizes that correspond to our Small, Large and Jumbo RetroFit doors. If you do not see a size that fits, or you still have questions, please do not hesitate to give us a call. This is a very common question and we can help avoid some of most common measuring mistakes.
For more information about how to measure your mailbox, please check out the following video: