Converted amount with unit and interpretation
The target-unit result and watt equivalent describe the same energy-transfer rate. Mechanical and metric horsepower remain separate choices; an energy total cannot be inferred without a duration.
To estimate appliance energy use and cost from power, operating time, and tariff, use the Appliance Electricity Cost Calculator and follow its own input conventions.
The formula
Convert through watts using the selected fixed unit factors. Btu per hour divides an International Table Btu’s joules by 3,600 seconds; the horsepower choices have different watt factors.
Verified worked example
A power rating of 2.5 kilowatts converts to 2,500 watts. At that constant rating for two hours it would transfer 5 kWh, but duration is not part of this conversion.
How to use this calculator
- Enter the known power rating or measured power amount.
- Select source and target units, using the correct horsepower convention when applicable.
- Read the labeled conversion and watt equivalent; apply operating duration separately for energy use.
Power input conventions
Power measures the rate of energy transfer. Unit conversion preserves that rate, so it cannot tell you a total energy amount unless time is separately known. The SI base-equivalent output is watts. A nominal equipment rating also may differ from actual operating power, especially where cycling, standby, or variable loading changes consumption.
Interpreting converted amount with unit
Mechanical and metric horsepower have distinct definitions and therefore different watt equivalents. Select the named convention rather than treating horsepower as one universal unit. Boiler horsepower and electrical horsepower are omitted to avoid silently substituting a different rating system. Btu per hour on this page uses the International Table Btu. This is a numerical scale conversion, not a determination of engine efficiency, electrical input current, or a household circuit’s capacity.
Assumptions & limitations
What this calculation assumes
- Horsepower is selected explicitly as mechanical or metric; Btu/h uses the International Table Btu.
What to keep in mind
- Mechanical and metric horsepower only; no boiler/electrical horsepower or equipment performance estimate.
Common questions
Is metric horsepower identical to mechanical horsepower?
No. Metric horsepower is 735.49875 W, while mechanical horsepower is approximately 745.699872 W. Choose the convention specified by the equipment source.
Does a kW rating predict my electric bill?
Only with operating duration, loading, and tariff information. Use an electricity-cost model with those inputs after converting the rating if needed.
Does this convert energy amounts?
No. Watts, horsepower, and Btu per hour are rates. An amount in joules, kWh, or Btu belongs in an energy converter.
Sources & further reading
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