Horsepower Calculator

Horsepower is a unit of mechanical power deeply embedded in automotive, marine, and industrial engineering. One mechanical horsepower equals 745.7 watts, or roughly 550 foot-pounds of work per second. Despite the name, the unit is entirely independent of any actual horse. It persists in engine specifications, equipment ratings, and trade literature worldwide, sitting alongside kilowatts (used in New Zealand and Australia) and metric horsepower or PS (common in Europe and Japan). Converting between these three scales is a frequent task when comparing imported vehicles, matching motors to machinery, or reading datasheets from different countries. This calculator handles two jobs. The first is computing the mechanical power output of a rotating shaft from its torque and speed. You enter the torque in Newton-metres and the shaft speed in RPM, and the tool returns power in watts, kilowatts, mechanical horsepower, and metric PS. This is useful when a motor datasheet gives rated torque at a specific speed and you need the equivalent power in a different unit. The second mode converts directly between horsepower and kilowatts. Both modes update instantly as you type. Use the figures for specification and comparison work; your vehicle or motor documentation remains the authoritative source for rated output.

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