The vernier scale adds an extra degree of accuracy to measurements. On the vernier scale, the smallest increment on the main scale is further divided.

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The metric vernier scale is divided into 50 equal parts. The measuring range of the vernier scale is usually 1mm, with each increment representing 0.02mm.

On an imperial caliper with a main scale of 6 inches, the vernier scale is 0.6 inch long, and is divided into 25 parts. Each increment has a length of 0.001 inch.