How to Read a Vernier Caliper

A Vernier Caliper is an engineering measurement tool used for precisely measuring dimensions such as width, length, outer diameter, inner diameter, and depth of a workpiece. It typically has a resolution of 0.05 mm or 0.02 mm, making it much more precise than a standard ruler.

Practice Reading with Interactive Visualization

Try sliding or typing numbers in the box below to observe the movement of the scales, and see how the Main Scale and the Vernier Scale work together.

Key Components for Reading

Reading a vernier caliper involves reading from two main scales:

1. Main Scale: The scale on the main body of the tool, with graduation marks similar to a standard ruler. The resolution is 1 millimeter (mm) per mark.
2. Vernier Scale: The sliding scale used to read fractional millimeter precision (for example, a resolution of 0.05 mm means 1 mark on the vernier scale equals 0.05 mm).

How to Read (3 Easy Steps)

1. Main Scale Reading: Observe where the "0" mark of the vernier scale (the sliding bottom scale) aligns with or passes on the main scale (the top scale). Read that as the integer value in millimeters.
2. Vernier Scale Reading: Look closely to find which mark on the vernier scale aligns exactly or most parallel with a mark on the main scale. Count which mark it is and multiply it by the tool's resolution (e.g., if the 16th mark aligns, calculate 16 × 0.05 = 0.80 mm).
3. Combine Both Values: Main Scale Value + Vernier Scale Value = Measured Value