Closing summary
The Power Converter converts electrical and mechanical power units. Watts and kilowatts map to mechanical horsepower, metric horsepower, BTU per hour, and foot-pounds per second using exact audited ratios with steps on every line.
Work and energy rate problems with force and distance belong on the physics Work Calculator. This page only relabels power already known in another unit.
Convert between units of power
Enter power in any supported unit and read the equivalent elsewhere. The Power Converter treats one watt as one joule per second exactly. Kilowatts suit motor nameplates and utility bills; horsepower suits US engine brochures and legacy machinery plates. Results update as values change.
A cascade view can list watt, kilowatt, mechanical hp, and metric hp together for one numeric entry.
Convert watts to horsepower
Mechanical horsepower, sometimes labeled hp(I) or imperial hp, equals 745.69987158227022 watts exactly. Seven hundred forty-six watts divide by that value to yield about 1.000 mechanical hp. The familiar 745.7 W approximation differs by less than 0.1 percent from the exact definition.
Multiply mechanical hp by 745.69987158227022 for watts. Two mechanical hp is about 1491.4 W. The Power Converter labels which horsepower definition is active.
Understand mechanical versus metric horsepower
Mechanical horsepower uses 745.69987158227022 watts per hp, rooted in the historical 550 ft·lbf/s definition. Metric horsepower, often labeled PS or hp(M), uses 735.49875 watts per hp, common on European car specs. The two differ by about 1.4 percent at the same numeric hp label.
A ninety-kW motor is about 120.6 mechanical hp or 122.4 metric hp. Quoting hp without naming the standard invites a small but real mismatch in compliance documents.
Convert kilowatts to horsepower
One kilowatt equals 1000 watts. Divide by 745.69987158227022 for mechanical hp: 75 kW ≈ 100.6 mechanical hp. Divide by 735.49875 for metric hp: 75 kW ≈ 101.97 metric hp. Electric vehicle specs often list kW; US marketing still converts to mechanical hp for comparison.
The Power Converter keeps both hp columns available from one kW input.
Convert foot-pounds per second and BTU per hour
Mechanical horsepower historically equals 550 ft·lbf/s. The Power Converter can express the same wattage as foot-pounds per second or as BTU/h for HVAC nameplates. One mechanical hp equals about 2544.43 BTU/h. When a motor plate lists both kW and BTU/h cooling load, convert through watts as the shared SI bridge so both labels reconcile.
Work a motor nameplate example
A 150 kW industrial motor equals 150000 W. Dividing by 745.69987158227022 yields about 201.1 mechanical hp, while dividing by 735.49875 yields about 203.9 metric hp. Export paperwork must state which hp definition the recipient expects because the two hp numbers differ at the same wattage.
FAQ
How many watts are in 1 horsepower?
One mechanical horsepower equals 745.69987158227022 watts. One metric horsepower equals 735.49875 watts. Pick the column that matches the engine plate or brochure.
Why do car hp numbers differ by region?
US listings often use mechanical hp while German PS figures use metric hp. The numeric label hp or PS looks identical but the watt count differs by about 1.4 percent.
How do I convert kW to hp?
Divide kilowatts times 1000 by 745.7 for mechanical hp, or by 735.5 for metric hp. The Power Converter performs either with the working shown.
Is horsepower the same as BTU per hour?
No, but both measure power rate. One mechanical hp equals about 2544.43 BTU/h. The Power Converter includes BTU/h in the unit list when heat-rate comparisons matter.
Where do I calculate kinetic power or motor torque?
Use physics solvers for torque, RPM, and mechanical power from force and velocity. The Power Converter only converts declared power units.
Which hp does the Power Converter use by default?
Mechanical horsepower unless metric hp is selected explicitly. Both factors stay in the table with full precision.
How many hp is 1000 watts?
One thousand watts divided by 745.69987158227022 equals about 1.341 mechanical hp, or about 1.360 metric hp. The Power Converter labels the column used.
What wattage is 200 metric hp?
Two hundred metric hp times 735.49875 W per hp equals 147099.75 W, or about 147.1 kW. Mechanical hp would yield a slightly lower kW at the same numeric hp label.
The Power Converter returns the converted value with the factor and working shown, so every result can be checked by hand against the audited conversion table.