A method is disclosed for operating an actuator having a coil and a displaceably mounted armature driven by a magnetic field generated by the coil, in a measurement operating mode for ascertaining a time at which the armature reaches its stop position after activation of the actuator. The method includes applying to the coil an actuation voltage signal dimensioned such that the expected armature stop time falls in a time window in which a temporally constant voltage is applied to the coil, detecting an intensity profile of the current flowing through the coil within the time window, and determining the armature stop time, based on an evaluation of the detected current intensity profile. A method for operating such an actuator is also disclosed, wherein information about the stop time is obtained in a measurement operating mode and used in a series operating mode for optimized actuation of the actuator.