Horsepower from Torque Calculator

About this calculator

This calculator converts engine torque and rotational speed into horsepower using the standard formula HP = (Torque in lb-ft × RPM) / 5252, a relationship derived from the definition of power as the rate of doing rotational work (P = τω) with the units folded into that constant 5252. It also gives the equivalent in kilowatts using P(kW) = τ(N·m) × RPM / 9549 (or via 1 hp ≈ 0.7457 kW).

Automotive engineers, tuners, and gearheads use this to convert dynamometer torque readings into the horsepower figures used in marketing and comparisons, and it's why torque and horsepower curves always cross at exactly 5252 RPM on a dyno chart. Enter the torque and RPM to get horsepower and kilowatts.