The Vernier caliper least counts formula is obtained by dividing the smallest reading on the primary scale by the total number of divisions on the Vernier scale.
Draw the diagram :
A small, movable auxiliary graduated scale that runs alongside a main graduated scale and is calibrated to display fractional parts of the larger scale's subdivisions.
The primary scale's smallest value that may be read is 1mm (indicated by a single increment).
The Vernier scale is divided into ten divisions.
The Vernier scale's movement is determined by how wide the jaws open. The basic objective of the Vernier scale is to improve the accuracy of the main scale reading by dividing the reading into smaller steps.