Abstract: A method for ascertaining a state of charge of an energy storage unit of a measuring device and/or a probable remaining operating time of the measuring device, includes capturing a plurality of voltage measured values for the voltage dropped across the energy storage unit and a plurality of current measured values for the current provided by the energy storage unit within a respective ascertainment interval. Subsequently, the state of charge associated with the respective ascertainment interval and/or the remaining running time associated with the ascertainment interval are ascertained in each case depending on the plurality of voltage measured values and current measured values. A measuring device for capturing a measured variable is also provided.