How to Read Vernier Micrometer Caliper Scales

It takes practice to properly read measurements from Vernier calipers.

Vernier calipers are highly precise instruments for measuring lengths and diameters of objects, typically to a precision of 0.05 millimeters. Vernier calipers consist of two primary parts: the caliper, which is usually marked in standard units of length, such as inches or centimeters, and resembles a comon ruler, and the Vernier, which is the adjustable, sliding scale on the bottom of the caliper that typically contains 11 evenly spaced marks with one of them clearly labeled 0 (zero).

Instructions

1. Place the object to be measured between the jaws of the calipers and close the calipers by sliding the Vernier until its travel stops. Do not use excessive force when closing the caliper.

2. Note the position of the "0" mark on the Vernier scale relative to the caliper scale. The position of the 0 will denote the first several digits of the measurements. For example, if the 0 on a centimeter (cm) Vernier caliper falls between the 1.5 and 1.6 marks on the caliper scale, then the first two digits of the measurement are 1.5 cm.

3. Determine the value for the final decimal place by noting which of the Vernier's marks aligns perfectly with one of the marks on the caliper scale. Only one Vernier mark will be correctly aligned--all of the others will be slightly offset. Count the position of this mark on the Vernier scale from zero to determine the final decimal place. For example, if the fourth mark from zero is aligned with a mark on the caliper scale, the final reading would be 1.54 cm.

References

• Southern Methodist University: Vernier Caliper
• University of Toronto: Reading a Vernier

Resources

• Southern Methodist University: Measurement, Calculations, and Uncertainty: Vernier Caliper Tutorial
• Clemson University: Using a Vernier Caliper