Engine Horsepower Calculator are used to estimate the engine horsepower of your vehicle based on the weight, the time, and the speed to finish a quarter mile run. The weight to be used should include the mass of the vehicle, the driver, the passenger, and other load. The results of these calculator are estimations only. Horsepower Calculation Method The ET Method This method uses the vehicle weight and the elapsed time (ET) to finish a quarter mile (402.3 meters). The Trap-speed Method This method uses the vehicle weight and the speed at which the vehicle finished a quarter mile (402.3 meters) . The speed to be used here should be the finishing speed at the quarter mile point. The RPM Torque Method This method uses the torque value from the vehicle manual book, The RPM should indicate the maximum torque output. Thanks for your support and do visit nitrio.com for more apps for your iOS devices.