How to Measure Sprockets for Chain Size

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A sprocket is a round metal wheel with teeth spaced evenly around it to support a chain in the same size as the sprocket. Sprockets power manual machines such as bicycles and motor-driven machines such as ATVs, motorcycles and electric scooters. Conveyor belts and agricultural equipment use sprockets with chains to turn belts and cultivate crops. Measuring the sprocket for its chain pitch and width allows you to buy the correct replacement chain.

Items you will need

  • Digital calipers

Press the "On/Off" button on the digital calipers to turn on the LCD display screen. Press the "mm/inch" button to select standard or metric measurements. Push the large jaws closed on the calipers, and press the "Zero" button to zero out the display.

Pull the large jaws apart, and place them in the center of the lower area on each side of one tooth on the sprocket. Read the digital display on the screen for the chain pitch.

Push the large caliper jaws back together, and press the "Zero" button to clear the measurement.

Pull the large caliper jaws apart, and place them horizontally on one tooth of the sprocket. Read the measurement on the screen for the sprocket width.


  • Chain pitch is the thickness of the chain that sits inside the teeth of a sprocket.
  • Chain width is the horizontal width of a chain that fits on a sprocket in the same width.