The calculation, without hidden assumptions
Power describes the rate at which energy is transferred, so electrical watts, mechanical horsepower and thermal BTU per hour can be compared on one physical basis. The trap is that not every “horsepower” is identical and BTU by itself is energy, not power. MAXScanner keeps mechanical hp and metric horsepower (PS) separate, uses BTU/h for thermal power, includes refrigeration tons as a rate unit, and links to electrical relationship calculators when voltage/current/power factor—not unit conversion—is the real question.
How to use this calculator
Enter the power rating and choose the exact unit written on the motor, appliance, HVAC or engineering document.
Choose the target unit; do not merge mechanical horsepower and metric PS when the source document specifies one of them.
Use the all-unit grid for cross-checking, then move to kVA/current/power-factor calculators only when you need an electrical relationship rather than a unit conversion.
Where people use it
- •Motor and engine specification conversion
- •HVAC heating/cooling rate comparisons
- •Electrical equipment power labels
- •Comparing mechanical hp, metric PS and SI watts
Example: 1 kW to horsepower
One kilowatt divided by 745.6998715822702 W per mechanical horsepower gives about 1.341022 hp. The same 1 kW is about 1.359622 metric PS, showing why the horsepower definition matters.
What the result does not assume
- •Power-unit conversion does not calculate electrical current, apparent power, efficiency or power factor. Use the dedicated electrical calculators for those relationships.
- •Refrigeration ton is a cooling-rate unit conventionally based on 12,000 BTU/h; it is not a unit of physical mass.
Frequently asked questions
How many horsepower is 1 kW?+
One kilowatt is about 1.341022 mechanical horsepower.
Is metric horsepower the same as hp?+
No. Mechanical horsepower is about 745.6999 W while metric horsepower (PS) is exactly 735.49875 W.
How many watts are in 1 BTU/h?+
Using the International Table BTU, one BTU per hour is about 0.29307107 W.
Can this convert kW to amps?+
No, because current also depends on voltage and, for AC systems, phase and possibly power factor. Use the dedicated Watts-to-Amps or three-phase calculator.
Semantic next steps
Continue the calculation
These links move to a different input, formula or project stage rather than a keyword variation of this page.
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MAXScanner keeps the formula and assumptions beside the result so you can verify the number before using it in a drawing, estimate, specification, worksheet or document. Where a supplier, manufacturer, drawing or applicable standard owns a requirement, that source remains authoritative.