A range is determined between two unsynchronized communications terminals in which a first terminal transmits a range request to a second terminal. The first terminal stores a first timestamp in memory corresponding to a time at which the range request message was transmitted. A range response is later received by the first terminal from the second terminal. The range response includes a residence time that characterizes an amount of time the second terminal required to send the range response after receiving the range request. The first terminal later stores a second timestamp in memory corresponding to a time at which the range response was received. Based on the second timestamp minus the first timestamp and the residence time, a roundtrip time for the range request is calculated. This roundtrip time can be used to calculate a distance between the first terminal and the second terminal based on the roundtrip time.