A method as well as a device are provided for determining the residual travel duration of a submarine, with which firstly for at least one certain travel situation a reference journey is carried out with which the power consumption of the submarine is detected as stored as a dependent-dependent consumption profile. Later, for the same travel situation, the residual travel duration or a residual capacity of a battery given a predefined travel duration is determined on the basis of the stored consumption profile and the current battery data.