Vernier Caliper:

LC = (Value of 1 Main Scale Division) / (Total number of vernier scale divisions)

In most of the Vernier Caliper’s, LC= 0.1 mm = [1mm / 10 divisions]

Screw Gauge:

Least count = (Value of 1 pitch scale reading)/ (Total number of head scale divisions)

In most of the Screw Gauge’s, LC= [1mm / 100 divisions] = 0.01 mm