Horsepower & Torque Calculator
Convert between horsepower and torque at a given RPM. Also calculate HP from trap speed or ET and vehicle weight.
HP and Torque Relationship
Horsepower and torque are mathematically related through RPM. Torque is the rotational force the engine produces. Horsepower is how fast that force is applied — it's work over time.
HP = (Torque × RPM) / 5252
At exactly 5,252 RPM, horsepower and torque are always equal. Below that RPM, torque is higher than HP. Above it, HP is higher than torque.
Trap Speed Method
The trap speed formula estimates wheel horsepower from your quarter-mile trap speed (the speed you cross the finish line at) and vehicle weight. This works because trap speed correlates closely with average power — it's less affected by traction than ET.
HP = Weight × (Trap Speed / 234)³
ET Method
The ET (elapsed time) formula estimates wheel HP from your quarter-mile time and vehicle weight. This method is more sensitive to traction and launch consistency than trap speed.
HP = Weight / (ET / 5.825)³
Wheel HP vs Crank HP
Both the trap speed and ET methods estimate wheel horsepower — the power actually reaching the ground. To estimate crank horsepower, add drivetrain losses: typically 15% for RWD manual, 17% for RWD auto, 20% for AWD.