Horsepower Calculator
Convert between horsepower, torque, watts, and kilowatts. Calculate HP from torque and RPM, convert watts to HP, or convert between different HP units.
About the Horsepower Calculator
Horsepower (HP) is the standard unit of power for engines in the United States, while Europe commonly uses kilowatts (kW) and metric horsepower (PS). The relationship between torque and horsepower is defined by HP = Torque × RPM / 5252 — notice that at exactly 5,252 RPM, an engine's torque and horsepower curves always cross. The constant 5,252 comes from converting foot-pounds per minute to horsepower. For understanding electrical power in comparison, our Electricity Cost Calculator works in watts and kilowatts.
One mechanical horsepower equals 745.7 watts, while one metric horsepower (PS, from German Pferdestärke) equals 735.5 watts — a difference of about 1.4%. When comparing European and American car specifications, this distinction matters. For electrical horsepower (used in motors), the value is exactly 746 watts. Use our Ohm's Law Calculator to analyze the electrical side of electric motors, converting between voltage, current, resistance, and power.
Related Calculators
Explore more free online calculators to help with your calculations
Take this calculation further
Browse the other calculators collection for more tools in this subject.
For a related calculation, use Density Calculator to solve for density, mass, or volume using D = M/V. Supports multiple unit systems with conversions. Alternatively, use Resistor Calculator to convert resistor color bands to resistance value, or convert a value to its 4-band color code.