rpm / speed / gear ratio calculator

With this calculator, you can solve for any of three variables in the rpm-speed equation.

You must leave a question mark "?" in the field that you are calculating for this to function properly.

Engine Speed (rpm)
Vehicle Speed (mph)
Rear End Gear (ratio)
Trans Gear (ratio)
Tire Width (mm)
Sidewall Height (%)
Rim Diameter (inch)