Gear Ratio Calculator

Gear ratio, rollout and speed for your drivetrain — highlighting unfavorable chainline combinations and overlapping gears.

1. Chainrings

1x 2x 3x

Chainring 1

Chainring 2

Chainring 3

Order doesn't matter — sorted automatically when calculating.

2. Rear sprockets (cassette)

Number of sprockets

Smallest sprocket (teeth)

Largest sprocket (teeth)

Rear sprocket teeth counts (comma-separated)

Filled automatically by the 'Calculate sprockets' button, which spaces the teeth evenly between the smallest and largest sprocket. Freely adjustable.

3. Wheel circumference

Tire size (ETRTO)

4. Cadence

Cadence (rpm)

Not calculated yet

Gear ratio ok Overlaps another chainring Extreme chainline (avoid)