When you choose horsepower, this calculator will measure the approximate horsepower of an engine based on the torque of the engine (measured in foot-pounds) multiplied by the RPM of the engine, divided by 5,252 (conversion between foot-pounds and horsepower). For example, if your engine has a torque of 350 pound-feet then the horsepower would be 333 horsepower, at 5,000 RPM.
When you choose torque, this calculator will measure the approximate torque of an engine based on the horsepower, multiplied by 5,252 (conversion between foot-pounds and horsepower), divided by the RPM of the engine. For example, if your engine has 350 horsepower then the torque would be 367 foot-pounds, at 5,000 RPM.