Disclosed is a method for determining actual lengths of short intervals, shorter than one segment of a toothed target of the crankshaft. The determination method includes: —a measurement step measuring first times, each corresponding to the time that the target takes to traverse a long interval of a length of a segment, and second times, each corresponding to the time that the target takes to traverse a short interval, —a correction step calculating a first ratio between two long intervals and a second ratio between two short intervals, —a step of obtaining the actual length of each of the long intervals, —a step of calculating a difference in length between two long intervals, —and a step of determining the respective actual lengths of a pair of short intervals of the toothed target.