These calculators are designed to give the approximate engine RPM (revolutions per minute) based on the ring gear and pinion gear ratio, the height of the tires (diameter from ground to top of the tire while mounted on the vehicle) and the transmission final gear ratio. This calculator requires the use of Javascript enabled and capable browsers.
This calculator does not take into consideration any drive train loss, road and weather conditions or driver skills. The calculated results are displayed; the higher the engine RPM, the greater the potential speed at the cost of fuel, heat, friction and engine longevity.
Results are only an Estimate - Your Mileage May Vary.
* auto = D in an AOD (1:1)
* AOD is calculated at .70 transmission ratio
* 5 speed is calculated at .80 transmission ratio
* Many late model vehicles have a taller overdrive ratio, such as Toyota Tacoma & Tundra
with 6 speed Auto have a .58:1 overdrive.
Use 1:1 RPM x .58 = RPM
Recommended RPM @ 100kph
| 4 cyl | 2200-3200 |
| 6 cyl | 2000-3000 |
| small block | 1800-2800 |
| big block | 1600-2600 |
| GM Duramax 6.2L | 1800-2800 |
| Ford Powerstroke (non-turbo) | 1600-2500 |
| Ford Powerstroke (turbo) | 1400-2200 |
| Dodge Cummins Diesel | 1400-2200 |
* auto = D in an AOD (1:1)
* AOD is calculated at .70 transmission ratio
* 5 speed is calculated at .80 transmission ratio
* Many late model vehicles have a taller overdrive ratio, such as Toyota Tacoma & Tundra
with 6 speed Auto have a .58:1 overdrive.
Use 1:1 RPM x .58 = RPM
Recommended RPM @ 100kph
| 4 cyl | 2200-3200 |
| 6 cyl | 2000-3000 |
| small block | 1800-2800 |
| big block | 1600-2600 |
| GM Duramax 6.2L | 1800-2800 |
| Ford Powerstroke (non-turbo) | 1600-2500 |
| Ford Powerstroke (turbo) | 1400-2200 |
| Dodge Cummins Diesel | 1400-2200 |
