**Vernier caliper least count:**

When it comes to reading of vernier caliper it includes its two major parts which are both main scale and vernier scale. Both are important but main scale needs less attention in this regard because reading of main scale is simple and easy like other non precision measuring tools such as steel rule or measuring tape and based on line graduated measurement but the focus is here how to read the vernier scale because it is used to measure the fractional values or we can say for measurement of precise values below the value of one main scale division that’s called its least count also. So we will discuss here what least count is and how to find out it for a vernier caliper.

**Definition:**

The lowest value of measurement that can be measured by a vernier caliper is called its least count.

Or

The minimum thickness or length value that a vernier scale can show during a measurement is its least count.

There is variety of vernier calipers is possible so each can has different least count if the vernier scale division is different from each other. Vernier caliper allowed readouts with in tenth of a millimeter for metric vernier calipers and 1/256 of an inch but it was initially on later as improved its precision it is possible to measure up to a least count 0.01 millimeter and 1/1000 of an inch.

**How to calculate least count:**

As explained above least count is specific value for each measuring instrument which can be more or less from another according to its specification so we can calculate it by formula given below.

Terminologies in formula:

VSD: Vernier Scale Division

MSD: Main Scale Division

N: Number of Divisions on Vernier scale

*N *VSD = (N-1) MSD

By simplifying that

VSD = (N-1)/*N* MSD (1)

As we know,

Least count= 1 MSD – 1VSD

By putting the value of VSD from equation 1,

= 1MSD – (N-1)/*N* MSD

By solving this, = [1-(N-1) *N *] MSD

So we get, Least Count=1MSD/*N*

This derivation is for interested persons only so we can only remember the formula for calculation. Let us say we calculate it for the vernier scale shown in under which has one main scale division of 1mm and on the vernier scale number of divisions are 10 so,

*1MSD= 1 mm, N =10*

**Least Count= 1MSD/N = 1/10 = 0.1 mm for this particular vernier scale.**