Power Converter
Convert between watts, kilowatts, horsepower, BTU/h, and more.
From
To
Result
745.7
Watt (W)
Common conversions
| Conversion | Result |
|---|---|
| 1 hp → W | 745.7 |
| 1 kW → hp | 1.34102186 |
| 1 MW → kW | 1000 |
| 1 BTU/h → W | 0.29307 |
| 1 kW → BTU/h | 3412.15409288 |
| 1 hp → kW | 0.7457 |
Power units in electrical and mechanical engineering
The watt (W) is the SI unit of power — one joule per second. Everyday appliances are rated in watts or kilowatts (kW), while large generators and power plants use megawatts (MW). In the automotive and mechanical world, power is often expressed in horsepower (hp): 1 hp = 745.7 W. HVAC equipment in the US is rated in BTU per hour (BTU/h) — 1 kW ≈ 3,412 BTU/h. Calorie/second and foot-pound/second are used in thermodynamics and classical mechanics respectively. All conversions route through watts and run entirely in your browser.
Built and maintained by Meet Shah · Last updated
What this tool is used for
- Comparing an appliance's wattage against a horsepower rating.
- Converting a heating or cooling output in BTU per hour into kilowatts.
- Reading a motor specification quoted in a different system.
- Sizing a supply against a load quoted in unfamiliar units.
- Comparing two devices' outputs in one consistent unit.
Frequently Asked Questions
- What is the difference between power and energy?
- Power is a rate; energy is an amount. A watt is one joule per second, so a 2 kW heater running three hours uses 6 kWh — power times time. Confusing them is why a bill quoted in kWh cannot be compared with an appliance rating in kW without knowing the hours.
- Which horsepower does the tool use?
- Mechanical horsepower, 745.7 W. It is not the only one: metric horsepower (PS or CV) is 735.5 W, about 1.4% smaller, and it is what most European car figures are quoted in. A 300 PS car is roughly 296 hp — exactly the gap that makes two spec sheets disagree.
- Why are air conditioners rated in BTU per hour?
- Historical convention in US HVAC, where BTU/h measures heat moved per hour. One BTU/h is 0.29307 W, so a 12,000 BTU/h unit is about 3.5 kW of cooling — and that is cooling capacity, not the electricity it draws, which is several times smaller.
- Where does 'horsepower' come from?
- James Watt's marketing. He needed to sell steam engines against draught horses, so he measured a horse turning a mill wheel and defined a unit customers could reason about — 33,000 foot-pounds per minute. It has been a fixed conversion factor ever since, unrelated to any actual horse.
- Is a 1000 W appliance always drawing 1000 W?
- No — that is usually the maximum. A 1000 W microwave delivers 1000 W of cooking power while drawing more from the wall; a motor's rating is its output at full load, not its idle draw. Rated power tells you the ceiling, which is what circuits are sized against.
Common errors and gotchas
- Confusing power with energy, where a watt is a rate and a watt-hour is a quantity.
- Using the wrong horsepower, since mechanical, metric and electrical definitions differ.
- Mixing BTU with BTU per hour, which are energy and power respectively.
- Comparing input power against output power without accounting for efficiency.
- Reading a peak rating as a continuous one, which is a specification difference rather than a conversion.
Related Converters tools
JSON to YAML
Convert JSON into clean, readable YAML instantly.
YAML to JSON
Convert YAML configuration into valid JSON.
JSON to XML
Convert JSON structures into nested XML markup.
HWB to HEX Converter
Convert an HWB color to HEX.
JSON to SQL
Turn a JSON array of objects into SQL INSERT statements.
CSV to XML
Convert CSV rows into structured XML records.
XML to CSV
Flatten repeated XML records into CSV rows.
INI to JSON
Parse INI config sections and keys into JSON.