Gear Ratio Calculator

14 days free trial Login

Gear ratio, development 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, freely editable)

Filled automatically by 'Calculate sprockets', but can be freely adjusted.

3. Combinations blocked due to chainline

Checked cells are blocked because the chain would run at too steep an angle. The outermost combinations are preselected — check or uncheck individual cells as needed.

4. Wheel circumference

Tire size (ETRTO)

Wheel circumference (cm)

Circumference estimated from the ETRTO size (rim diameter + 2x tire width) — the real rolling circumference can differ by +/-1-2%.

5. Cadence

Cadence (rpm)

Tolerance (+/- %)

Not calculated yet.

gear ratio ok overlaps another chainring blocked (chainline too steep)

Chart: chainline

also show overlapping gears (yellow) also show blocked gears (red)

Cycling training plan | Triathlon training plan | Running training plan | Crosscountry ski training plan |

Chart: chainline

Comparison