Methods, systems, apparatus, and computer programs encoded on computer storage medium, for receiving a set of expected activities, each expected activity in the set of expected activities including an activity that is expected to be performed by a computing device, determining one or more time periods based on the set of expected activities, determining one or more expected rates of change of state of charge (SOC) of a battery of the mobile computing device by, for each time period of the one or more time periods, determining an expected rate of change of SOC based on a base rate of change of SOC and one or more expected activities associated with the time period, and determining an estimated remaining time based on the one or more expected rates of change of SOC, the remaining time corresponding to a time at which an expected SOC is less than a threshold SOC.