Learn how to use the original and most popular gear calculator for cyclists

The following instructions aim to assist you in effectively using our bicycle gear calculator, ensuring a more seamless and informed experience.

Gear Ratio. Count the number of teeth on the front cog of your bicycle, and select this value in the picker labeled chainring. Then do the same on your rear cog for the picker labeled sprocket.

Gear Inches. Following on the steps to calculate the gear ratio, measure in millimeters the thickness of your rear tire across its tread when inflated, and select this value in the picker labeled tire thickness. Then do the same with the diameter of your rim up to its bead for the picker labeled rim diameter. If you're measuring in inches, please refer to our article explaining how to convert tire sizes to the international standard (ISO 5775).

Development Meters. Follow the same procedure as when calculating gear inches with tire and rim sizes measured in millimeters. Sometimes, a marking can also be found printed on the sidewall of the tire. If in doubt, please refer to our article explaining how these tire markings are designated.

Gain Ratio. Following on the steps to calculate development meters, measure in millimeters the length of your crank arm from the center of its pedal to the center of your bottom bracket, and select this value in the picker labeled crank arms length. Sometimes, a marking can also be found engraved on the interior of the arms.

Speed. Following on the steps to calculate development meters, drag the slider horizontally to select a value for the field labeled cadence.

Note: Selecting the metric value in the picker labeled measurement system will convert the speed to kilometers per hour (km/h), whereas selecting imperial will instead convert to miles per hour (mi/h).

For more information, please visit our articles answering common questions from the community.