The invention relates to a method for determining a separation, spacing or distance of an object from an ultrasonic sensor, in which ultrasonic pulses are emitted by a transducing or sensing element and in which ultrasonic pulses reflected by the object are detected by the same transducing element. According to the invention, the method is characterized in that there is a spectral analysis of the signal detected by the transducing element, that the multiple echo frequency attributed to multiple echoes of the ultrasonic pulses is determined in the spectrum of the detection signal and that on the basis of the multiple echo frequency the separation of the object from the ultrasonic sensor is determined. The invention also relates to an ultrasonic sensor for determining the separation of an object.