Overview
Gear Ratio Calculator
Calculate tooth ratios, RPM, theoretical road speed, and final drive on iPhone and iPad, with metric and imperial units.
What it does
- Free tooth-count gear ratios and input/output RPM in both directions.
- Lifetime Pro: speed, required RPM, final drive, comparisons, percentage changes, and target tooth combinations.
- Named local saved setups and a lightweight 20-entry calculation history with Pro.
- On-device calculations, native controls, light and dark appearance, and iPad sidebar navigation.