Power Converter
Convert watts, kilowatts, horsepower, and BTU per hour.
This power converter, power conversion calculator, and electrical power conversion calculator switches between common power units - watts, kilowatts, horsepower, and BTU per hour - each conventional in different fields from electronics to automotive engineering to HVAC.
Enter a power value in any supported unit, and the calculator returns the equivalent in your chosen target unit.
Worked Calculation Examples
| Scenario | Result | Calculation Step |
|---|---|---|
| 250 horsepower to kilowatts | ≈186.4 kW | 250 × 0.7457 ≈ 186.4 kW. |
| 1,500 watts to BTU per hour | ≈5,118 BTU/hr | 1,500 × 3.412 ≈ 5,118 BTU/hr. |
Key Power Conversion Factors
1 horsepower = 745.7 watts (mechanical horsepower) = 0.7457 kW. 1 watt = 3.412 BTU per hour. These power conversion factors matter when comparing specifications across fields that traditionally use different units - like comparing an engine's horsepower rating to an electric motor's kilowatt rating.
Power vs. Energy: A Common Mix-Up
Power (watts, horsepower) measures the rate of energy use or production at an instant, while energy (joules, kWh) measures a total quantity accumulated over time - a 1,000-watt device running for 1 hour consumes 1 kWh of energy, illustrating how the two concepts relate but aren't interchangeable.
How to Use the Power Converter
- Open the Power Converter and enter the values requested in the input fields.
- Check the units, percentages, dates, or time periods before reading the answer.
- Review the instant result and adjust any value to compare another scenario.
- Use the formula, example, and FAQs below to understand how the power converter works.
Frequently Asked Questions
How do you convert horsepower to watts?
Multiply the horsepower value by 745.7 to convert to watts, using the standard mechanical horsepower conversion factor.
What is the difference between power and energy?
Power measures the rate of energy use at a given moment (like watts), while energy measures a total accumulated amount over time (like kilowatt-hours) - power multiplied by time gives energy.
How many watts are in 1 kilowatt?
1 kilowatt equals exactly 1,000 watts, since 'kilo' is the metric prefix for one thousand.
How do I use this power converter?
Enter the known values, review the units or settings, and the calculator updates the result instantly. The formula and example on this page show how the answer is produced.
What does the Power Converter calculate?
Convert watts, kilowatts, horsepower, and BTU per hour. It is designed for fast browser-based calculations without sign-up, downloads, or manual spreadsheet setup.
What formula does this power use?
The formula is: target = source * conversion factor. James Watt, the unit's namesake, defined 'horsepower' himself in the 1780s as a marketing tool - he needed a way to convince potential customers how many horses his steam engines could replace, reportedly basing his estimate on observing how much work a strong horse could do at a mill, a figure now considered to overestimate typical horse output but which nonetheless stuck as a permanent unit of measurement.
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Last updated: September 27, 2026.