Calculate your final drive gear ratio from the ring and pinion tooth counts and see how it affects engine speed on the highway. The ratio is simply the ring gear teeth divided by the pinion teeth, so a 41 tooth ring on a 11 tooth pinion gives a 3.73 ratio. This calculator also estimates engine RPM at a chosen cruising speed using your tire diameter and top gear ratio, which is the number that decides how relaxed or busy your engine feels on a long drive. A numerically higher axle ratio improves acceleration and towing but raises cruising RPM and fuel use, while a lower one does the opposite. Use it when swapping axles, choosing a differential, or picking tires. Everything is computed locally in your browser with no data sent anywhere.
It divides the ring gear teeth by the pinion gear teeth to give the axle or final drive gear ratio.
It uses the gear ratio and tire size to relate wheel speed to engine speed, giving RPM at a chosen road speed.
Larger tires turn fewer times per mile, which lowers engine RPM at a given speed for the same gearing.
Calculate your final drive gear ratio from the ring and pinion tooth counts and see how it affects engine speed on the highway. The ratio is simply the ring gear teeth divided by the pinion teeth, so a 41 tooth ring on a 11 tooth pinion gives a 3.
Yes. Gear Ratio Calculator is completely free, with no sign-up and no usage limits.
Yes. Gear Ratio Calculator runs in any modern web browser. There is nothing to download or install.
Yes. Gear Ratio Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.