Bike Cadence and Speed Calculator

This tool converts between cycling cadence and speed using your chainring, cog, and wheel setup. Switch modes to find how fast you ride at a target RPM, or what cadence you need to hold a given speed.

The Formulas

speed = π × wheel diameter × gear ratio × cadence

cadence = speed / (π × wheel diameter × gear ratio)

Wheel diameter should include tire width. Gear ratio is chainring teeth divided by rear cog teeth. Cadence is in RPM and speed can be shown in km/h or mph.

When to Use Each Mode

Cadence to speed: Plan training intervals or check expected speed at your preferred RPM in a given gear.
Speed to cadence: Enter GPS speed to see whether you are spinning too fast or grinding too slow in your current gear.

Frequently Asked Questions

How do I estimate cadence without a sensor?

Count pedal revolutions for 15 seconds and multiply by 4, or count for 60 seconds for the most accurate estimate. A longer count window improves accuracy.

What wheel and tire values should I enter?

Common road setups use 27 or 28 inch effective diameter. Mountain bikes often use 27.5 or 29 inch wheels. Add tire width if your rim size does not already include it.

Can I use this for indoor trainers?

Yes, if you know your gear and wheel or roller diameter. Smart trainers may report speed directly, which you can convert back to cadence with the speed mode.

Why does a bigger chainring increase speed at the same cadence?

A larger chainring raises the gear ratio, so each pedal stroke turns the rear wheel farther. That increases road speed without changing cadence.

How is this different from a bike cadence calculator?

A cadence-only calculator typically starts from speed. This tool works both ways, so you can solve for cadence or speed with the same drivetrain inputs.

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Bike Cadence and Speed Calculator