Distance between two ZIP codes
How the distance is measured
Each ZIP code is placed at one point: the Census Bureau's internal point of its ZIP Code Tabulation Area, a coordinate guaranteed to fall inside the area, or the post office's location from GeoNames for a ZIP code with no area (PO boxes, single organisations). The result is the great-circle distance between the two points, the shortest path over the Earth's surface, in miles and kilometres.
It is a straight line, not a driving distance: roads, rivers and mountains add to it, typically by a fifth to a third in open country and more in the mountains or around water. Two neighbouring rural ZIP codes can be many miles apart centre to centre while sharing a boundary. Each answer card shows the city, county and time zone of both ZIP codes, and says when the two are in different time zones.