Abstract: A method and an electronic slide caliper serve for measuring a length. The slide caliper comprises a rule and a slide which is arranged on the rule for longitudinal displacement and which is provided with two sensors which are offset relative to each other in the longitudinal direction in such a way that the zero passages of the signals generated by the sensors will not coincide. In order to be able to measure the lengths even in the presence of considerable drifts, the zero passages (ND) of the signals are determined by determining first maximum values (MX) and minimum values (MN) of the signal values (U) and deriving thereafter the zero passages (ND) as arithmetic mean value. By taking the average of a larger number of zero passages one then determines the respective zero level (U.sub.N).