A power converter moves a value between watts and kilowatts (SI), the two horsepowers (mechanical and metric), and BTU per hour (heating and cooling). It converts your value into a base unit — watts — and back out. The thing to watch is that there are two horsepowers: mechanical hp at 745.7 W and metric PS at 735.5 W, about 1.4% apart, so a European "100 PS" car is roughly 98.6 hp. This tool labels them separately to keep the comparison honest.
Reviewed: June 20, 2026 · Author: Naveen P N, Founder — AI Calculator · Verified against: SI and horsepower definitions, recomputed in code.
How the conversion works
Each unit equals a fixed number of watts: a kilowatt is 1000 W, mechanical horsepower 745.7 W, metric PS 735.5 W, and a BTU/h about 0.293 W. Multiply your value by the "from" unit's watts-per-unit to reach watts, then divide by the "to" unit's. Since a watt is one joule per second, power and energy are tied: run a 1000 W device for an hour and you've used 1 kWh of energy.
Worked example — 1 horsepower in other units
Scenario: convert 1 mechanical horsepower to other power units.
One mechanical horsepower is 745.70 W (0.7457 kW), about 1.014 metric PS, or 2544.43 BTU/h. The everyday cases follow the same rule: 1 kW is 1.34102 hp (1.35962 PS), and a 3.5 kW air conditioner is roughly 12,000 BTU/h. The converter shows every unit at once, which is exactly what you need when a US spec is in hp and a European one in PS.
Frequently Asked Questions
× 1.34102 (mech hp) or × 1.35962 (metric PS). 100 kW ≈ 134 hp.
Mechanical hp = 745.7 W; metric PS = 735.5 W (~1.4% apart). 100 PS ≈ 98.6 hp.
745.7 W (mechanical) or 735.5 W (metric PS).
× 3412.14. 3.5 kW ≈ 12,000 BTU/h (1-ton cooling).
Power is energy ÷ time (1 W = 1 J/s). For energy totals use the Energy Converter.