The pitch value P of a chiral nematic liquid crystal is a critical parameter fin. azimuthal anchoring strength measurement. The Grandjean-Cano wedge method is a conventional technique for pitch determination, but the perfect wedge cell with known angle and uniform disclination lines are required. In this work, we have developed an improved Grandjean-Cano method, which is simple and gives accurate pitch value. The sensitivity of this new method is +/-lambda/2 Delta n.