RPM to kMH Calculation

Speed of the motor in v(kMH) in kilometer per hour is equal to 0.1885 times of the speed N(RPM) multiply by diameter D(m) in meter. The formula for converting Rpm to kmph formula can be written as,

Vehicle speed = 0.1885 * Wheel RPM * diameter of the tire.

v(kMH) = 0.1885 * N(RPM) * D(m)

Look at this formula, the speed is directly proportional to the rpm and the diameter of the driving mechanism.



Example:

Let us calculate the rpm to kmh of the car; the 250 mm diameter of the tire is rotating at 980 revolution per minute.

Apply our formula,

Speed of the car in kMH = 0.1885 * 980 * 0.25 = 43.2 kmph.