A method of measuring the read-to-write offset of a track in a disc drive system having separate read and write elements by measuring read error rate as a function of incremental actuator offset. The actuator is incrementally moved from one edge of the track to the other. The two radial positions which produce read error rates within acceptable limits are identified, and the read-to-write offset is determined by subtracting the offset at which the track was written, from the midpoint of the two radial positions. The read-to-write offset for each track accessed by the transducer is calculated from the read-to-write offset measured at the track.