1. A method comprising: determining a location of a mobile device; determining, based on account information of a user of the mobile device, an address associated with the user; determining assumed geographic coordinates of the address; confirming that the assumed geographic coordinates indicate a geographical location of the address in response to determining that a plurality of conditions have been satisfied, the plurality of conditions including: a first condition that the location of the mobile device is designated as a significant location of the user, wherein the mobile device designates the location of the mobile device as the significant location upon determining that, according to a series of location readings, the mobile device stayed for more than a threshold amount of time at the location; and a second condition that a distance between the significant location and the assumed geographic coordinates satisfies a match threshold distance that corresponds to a count of the location readings in the series, wherein a lower count corresponds to a larger match threshold distance; and upon the confirming, storing the assumed geographic coordinates in association with the address, wherein the method is performed by one or more computing devices.