Dial indicators are designed as an  instruments used to accurately measure a small distance. They may also be known as a dial gauge, dial test indicator (DTI), or as a "clock". They are named so because the measurement results are displayed in a magnified way by means of a dial.

Dial indicators may be used to check the variation in tolerance during the inspection process of a machined part, measure the deflection of a beam or ring under laboratory conditions, as well as many other situations where a small measurement needs to be registered or indicated. The definition of small depends on the observer however a range between 1 mm (0.040") and 50 mm (2") may be thought of as typical with a travel of 10 mm (approx 0.5") being perhaps the most common.