Provided is a process of determining a future battery level of one or more battery-powered computing devices, the process including: accessing an event record in memory describing a scheduled event in which a user of a plurality of computing devices is scheduled to participate, inferring a subset of the plurality of computing devices to be used in that time period, determining present battery levels of the computing devices, the levels being values indicative of an amount of energy stored by batteries, determining present usage rates of battery energy, inferring battery outlooks corresponding to the scheduled event, a battery outlook being an estimated amount of energy consumption attributable to the scheduled event, and predicting future battery levels of computing devices based on at least a present battery level, a present usage rate, and a battery outlook corresponding to the scheduled event.