The least count of a Vernier caliper, also known as the Vernier constant, is the smallest measurement that can be accurately read using the instrument. It is defined as the difference between one main scale division (M.S.D) and one Vernier scale division (V.S.D).
The formula for calculating the least count (L.C) of a Vernier caliper is:
L.C=1 M.S.D−1 V.S.D
For most standard Vernier calipers, the least count is typically 0.02 mm, which allows for precise measurements of small dimensions.