The house number is the official identifier of a property's location on a street or within a grid. The house number is normally shown in conjunction with the street name (e.g. 123 Main Street, where '123' is the house number).

House numbers may contain extensions, such as letter or numbers, which divide a property (e.g. 555-A and 555-B). A house number may be used as a postal delivery identifier, or it may simply designate part of a range of possible delivery numbers along the edge of a property.

House numbers are often shown as a whole range which includes the most commonly used single number within that range. This range covers all applicable house numbers from one corner of the property to the next, regardless of whether each number in the address range is actually assigned to an entrance or used for postal delivery.