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Power Conversion
Tool Description
Power Conversion is an online power unit converter with daily free quota — no installation, no registration, ready to use. It supports mutual conversion between 15 power units, including SI units (W/kW/MW/GW/mW/µW), horsepower (mechanical/metric), thermal power (BTU/h/cal/s/kcal/h/RT), electronic power (dBm), and mechanical power (ft·lb/s). Enter any value and unit to instantly view results in all units. All calculations run entirely in your browser, 100% privacy protected. Whether for electrical engineering, HVAC, automotive power, or wireless communication, its easy to handle — start using it free with results comparable to professional engineering software.
How to Use
- Enter a value
Type the power value you want to convert, supporting integers and decimals, e.g.,
1000,0.75 - Select source unit
Choose the power unit of your value from the dropdown (W/kW/MW/GW/mW/µW/hp/PS/BTU/h/cal/s/kcal/h/dBm/RT/ft·lb/s)
- View results
Click the "Convert" button or press Enter, and the result area below will display the corresponding values in all units. Each result has a copy button for convenience.
Use Cases
- Electrical Engineering: Convert motor power and power station output between W/kW/MW/GW, e.g., a wind turbine 2 MW = 2,000 kW
- HVAC & Refrigeration: Convert cooling capacity between BTU/h, tons of refrigeration (RT), and watts; 1 HP ≈ 2,500 W ≈ 8,530 BTU/h
- Automotive Power: Convert engine horsepower (hp) to metric horsepower (PS) and kilowatts to understand vehicle specs from different countries
Key Advantages
- Daily Free Quota
Free usage is provided every day. Just open the page and use it — no software to download or install, so daily conversions cost nothing.
- Private and Secure
All conversions run locally in your browser using pure JavaScript math; your input never leaves your device, keeping your data private.
- Broad Unit Coverage
Covers 15 units across SI, horsepower, refrigeration, thermal, and electronic power—one entry yields all results for both engineering and daily needs.
- dBm Supported
Uniquely supports decibel-milliwatt (dBm), a logarithmic unit where negative values represent weak signals—a practical tool for wireless and RF engineering.
- Reliable Precision
Uses internationally standardized ratios (e.g., 1 hp = 745.699872 W) with double-precision and logarithmic math for accurate, trustworthy results.
- Easy Copy
Each result has a copy button on the right, letting you copy values with one click for use in documents, spreadsheets, or chat tools.
SI Power Unit Conversion
The following table shows the conversion relationships between SI power units, using watt (W) as the base unit:
| Unit Name | Abbr. | Conversion Relationship | Equivalent W |
|---|---|---|---|
| Microwatt | µW | 1 µW = 0.001 mW | 0.000001 |
| Milliwatt | mW | 1 mW = 0.001 W | 0.001 |
| Watt | W | 1 W = 1,000 mW | 1 |
| Kilowatt | kW | 1 kW = 1,000 W | 1,000 |
| Megawatt | MW | 1 MW = 1,000 kW | 1,000,000 |
| Gigawatt | GW | 1 GW = 1,000 MW | 1,000,000,000 |
Horsepower & Thermal Power Unit Conversion
The following table shows the conversion relationships for horsepower, thermal power, and refrigeration units, using watt (W) as the base unit:
| Unit Name | Abbr. | Conversion Relationship | Equivalent W |
|---|---|---|---|
| Horsepower | hp | 1 hp = 550 ft·lb/s | 745.699872 |
| Metric Horsepower | PS | 1 PS = 75 kgf·m/s | 735.49875 |
| BTU per Hour | BTU/h | 1 BTU ≈ 1,055 J | 0.29307107 |
| Calorie per Second | cal/s | 1 cal = 4.1868 J | 4.1868 |
| Kilocalorie per Hour | kcal/h | 1 kcal/h = 1000 cal/h | 1.163 |
| Ton of Refrigeration | RT | 1 RT = 12,000 BTU/h | 3,516.85284 |
| Foot-pound per Second | ft·lb/s | 1 ft·lb/s = 1.355818 W | 1.355818 |
About dBm (Decibel-milliwatt)
dBm is a logarithmic power unit commonly used in wireless communication and RF engineering, representing the power ratio relative to 1 milliwatt (mW): dBm = 10 × log₁₀(P / 1 mW). 0 dBm = 1 mW, 30 dBm = 1 W.
Since dBm is logarithmic, it cannot represent zero or negative absolute power. When the source unit is dBm, you can enter any real number (including negative values, e.g., -30 dBm = 0.001 mW); other units only accept non-negative values.
dBm is widely used in Wi-Fi signal strength, Bluetooth transmit power, and fiber-optic communication. For example, a typical Wi-Fi router transmits at about 20 dBm (100 mW), and cell phone signal strength ranges from -50 to -120 dBm.
FAQ
1 mechanical horsepower (hp) = 745.699872 W ≈ 745.7 W; 1 metric horsepower (PS) = 735.49875 W ≈ 735.5 W. The difference is approximately 1.4%. Mechanical horsepower (hp) was defined by James Watt and is mainly used in the UK and US; metric horsepower (PS) originated in Germany and is widely used in Europe and Asia. In the Chinese automotive market, "horsepower" usually refers to metric horsepower (PS).
1 HP ≈ 2,500 W (cooling capacity), equivalent to approximately 8,530 BTU/h or 0.71 tons of refrigeration (RT). The "HP" here refers to the compressor input power, not the cooling capacity itself. When selecting an AC unit, 1 HP suits a 10-15 m² room, and 1.5 HP suits a 15-22 m² room. Also, 1 ton of refrigeration (RT) = 12,000 BTU/h ≈ 3,517 W.
BTU (British Thermal Unit) is the amount of heat required to raise the temperature of 1 pound of water by 1°F. As a power unit, 1 BTU/h ≈ 0.293 W; conversely, 1 W ≈ 3.412 BTU/h. BTU/h is widely used in US air conditioning and heating equipment. For example, a 12,000 BTU/h AC unit (i.e., 1 ton of refrigeration) has a power of about 3,517 W.
dBm (decibel-milliwatt) is a logarithmic power unit referenced to 1 milliwatt. When the source unit is set to dBm, you can enter negative values. For example, -30 dBm = 0.001 mW (1 µW), indicating an extremely weak signal. 0 dBm = 1 mW, 30 dBm = 1 W. Other power units cannot be negative due to physical constraints.
No. All conversion calculations run entirely in your browser using pure JavaScript math. Your input data never leaves your device.
This tool uses JavaScript double-precision floating-point numbers (64-bit IEEE 754) with internationally standardized conversion ratios (e.g., 1 hp = 745.699872 W, 1 BTU/h = 0.29307107 W). Decimal portions are capped at 6 significant decimal places, and excessively long decimals are automatically truncated. For dBm conversion involving logarithmic operations, results are properly rounded. Accuracy is sufficient for the vast majority of practical scenarios.
It supports 15 power units: SI (µW, mW, W, kW, MW, GW), horsepower (hp, PS), thermal/refrigeration (BTU/h, cal/s, kcal/h, RT), electronic power (dBm), and mechanical power (ft·lb/s). Enter a value in one unit and the others are calculated automatically.
Free usage is provided every day, so daily use costs nothing. We prepare a daily free quota for every user, which is enough for basic power conversion and engineering references without registration; if you need more frequent or professional use, a membership unlocks more benefits.
Yes. The page is responsive and works on phones, tablets, and desktop browsers alike. On mobile, simply tap the input, choose a unit, and tap convert to see results, just like on desktop.
Batch input is not yet supported. The current version converts one value at a time, but a single entry yields results for all 15 units at once, which covers most engineering and daily scenarios.
Because dBm is a logarithmic ratio unit. 0 dBm = 1 mW, and negative values represent power below 1 mW (e.g., -30 dBm = 0.001 mW), commonly used for weak RF signals. This tool allows any real number when dBm is the source unit; other units only accept non-negative values.
Click the copy icon on the right of the result box. Each unit result has a copy button that copies the value to your clipboard with one click, ready to paste into a document, spreadsheet, or chat window without manually selecting text.
Content last updated：2026-07-16
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