These are examples of house number plaques I've created for people. The 19101 sign is double sided, made to hang beneath a roadside mailbox. Each side is painted in different colors. All the signs are 7.25" x 16." The regulations in my county say that house numbers need to be at least 4" high so they are easily visible from the street or road, especially for emergency personnel such as police or ambulances (firefighters can probably figure out their destination without a house number). I use bold, bright colors to enhance visibility of the house number. I'm constantly amazed at how invisible house numbers are.