How does a 3x9 compare to a 2x10 or 1x11 drivetrain?

This handy little calculator can tell you that plus many more combinations! Watch this video for an overview or just scroll down to the calculator.

Enter the wheel size, tire size, number of chain rings, number of teeth, select a cassette size (and optionally the individual cogs) and this tool will help you figure out how much easier or harder your gearing will be if you switch it or buy a new bike with different gearing that your current bike. It can also help you identify any duplicate gear combinations you might have.

Do you want to see gear inches (the classic artificial number everyone normally uses) or development (the actually distance in inches one pedal revolution takes you in the selected gear)?

Bike 1 Bike 2
Wheel Size:
Tire Size:
# Chainrings:
Low Gear:
High Gear:
Approx. Max Speed at 90 RPM:
Gear Inches:


  1. Cassettes marked with an * are made using either a OneUp 16+40 or 16+42 or Wolf Tooth 40 or 42 tooth conversion. The 16+ options give you a much more even progression through the gears.
  2. Gear inches = wheel diameter in inches * (number of teeth in front chainring)/(number of teeth in rear sprocket).
  3. Development = the distance (in inches) your wheel travels for one revolution of the pedals in any particular gear.