Engine Horsepower Calculator
Estimate engine power using ET Method, Trap-Speed Method, or Torque + RPM
Estimates engine horsepower from vehicle weight and the elapsed time (ET) to finish a quarter mile (402.3 m).
Estimates engine horsepower from vehicle weight and the trap speed at the end of a quarter mile run.
Calculate horsepower directly from engine torque and RPM. This is the standard dyno / engineering method.
🔄 Quick Power Unit Conversions
⚙️ What is Horsepower?
Horsepower was coined by engineer James Watt in the 19th century to compare the output of steam engines to horses. He measured that a horse could do 33,000 foot-pounds of work per minute — that became 1 HP. Today it's the standard for rating engine output.
📊 Gross vs Net Horsepower
Gross HP — measured at the crankshaft on a dyno, without engine accessories connected. Net HP — measured with all accessories (alternator, water pump, power steering) connected. Net HP is what reaches the wheels and is lower than gross HP.
🔧 Horsepower vs Torque
Torque is rotational force; horsepower is the rate at which that force does work. At 5,252 RPM, an engine's horsepower and torque numbers are always equal. Below that RPM, torque > HP. Above it, HP > torque.
⚠️ Safety Notice
Quarter-mile runs should NEVER be done on public roads. Use licensed drag strips or private tracks only. Always ensure your vehicle is in proper working condition before any high-performance testing.