Gear Ratio, Final Drive, RPM & Vehicle Speed Calculator (Transmission Math)
Calculate exact theoretical vehicle speed (km/h and mph) for any engine RPM, transmission gear ratio, differential final drive ratio, and tire diameter, or find cruising RPM at highway speed.
Calculated Vehicle Speed (km/h)
Calculator Inputs
Calculated Vehicle Speed (km/h)
Vehicle Speed in MPH
Engine RPM at 100 km/h (62 mph)
Calculated Vehicle Speed vs Cruising RPM at 100 km/h
Automotive engineering and motorsport drivetrain calculation tool. Assumes negligible tire slip.
This calculator is designed for educational and informational purposes based on publicly declared statutory frameworks. The outputs do not constitute binding financial, tax, or legal advice. We assume no liability for decisions made based on these estimates. Always verify with the relevant official authorities or a certified professional advisor.
Calculation Methodology
Total Ratio = Transmission Gear Ratio * Differential Final Drive. Axle RPM = Engine RPM / Total Ratio. Speed (mph) = (Axle RPM * PI * Tire Diameter in * 60) / 63,360. km/h = mph * 1.60934.
Frequently Asked Questions
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