Calculate Change Gears

The ratio may look simple: (A/B * C/D), but finding the right pair of change gears to hob your gear, or run your machine, can be a serious pain. This calculator determines change gears for a given number of teeth in your gear, and the machine's constant.

Our calculator uses change gears from 20-130 teeth, and ranks solutions to keep teeth count similar across the change gears. We know there are a still a lot of possible combinations, so we've reduced the results to show common rations (1:1, 1:2, 1:3, 2:3). For example, if 2:3 appears then any change gears with a 2:3 ratio will work for that spot: 20/30, 40/60, 54/81, etc.

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Enter Number of Teeth:

Change Gear calculator for different machine constants