A dial indicator is used to display small measurement changes in an amplified form in order to make them more relevant to those monitoring the readings. The gradations measured with a dial indicator are small, typically 0.001 inch to 0.100 inch.
Dial indicators can be analog, with a needle pointing to gradations along a circular array. They can also be digital, displaying measurements on a digital display. Applications for dial indicators include calibrating machinery, centering metal lathes and ensuring accuracy in a manufacturing process. Some dial indicators measure linear displacement while others measure angular displacement. The part of a dial indicator that comes into contact with the item being measured is called an indicator tip. On some dial indicators the indicator tips are interchangeable to suit multiple applications.