Power

Convert power between watts, kilowatts, mechanical and metric horsepower, BTU per hour, and calories per second in your browser. No upload, no signup — your numbers stay on your device.

Conversions

Output

1000

Milliwatt

1 Watt → Milliwatt

How was your conversion?

Power rating: 4.8 / 5.0 (25 reviews)

About Power Converter

Power Converter handles rate-of-work units across electrical, mechanical, and thermal conventions: watts and kilowatts (SI), horsepower (mechanical at 745.7 W and metric/PS at 735.5 W), BTU per hour (HVAC sizing), and calories per second (thermodynamics and nutrition rate problems). The tool exposes both horsepower definitions so a car-brochure PS figure does not get confused with a UK/US hp rating, useful when comparing engine specs across EU and US literature. One input refreshes every other unit at once — no re-clicks. The page runs statically in your browser and works offline after first load.

Best for

  • Comparing EU PS-rated engine specs with US mechanical-horsepower ratings
  • Sizing HVAC equipment where cooling capacity is in BTU/h and electrical draw in kW
  • Thermodynamics homework where calories-per-second meets watts

Pros

  • +Mechanical hp, metric PS, electrical W, thermal BTU/h — all in one panel
  • +Uses exact SI definitions (1 hp = 745.6999 W, 1 PS = 735.49875 W)
  • +Offline after first load; nothing entered leaves your device

Cons

  • −Apparent power (VA) and reactive power (VAR) for AC circuits are not included
  • −Doesn't derate for efficiency or power factor — pure unit math

How to use Power Converter

  1. 1

    Enter the source value, color code, or parameters in the input fields.

  2. 2

    Select the source and destination units or models from the option dropdowns.

  3. 3

    Watch the output update instantly in real-time as you type or adjust.

  4. 4

    Copy the converted results to your clipboard with a single click.

Frequently Asked Questions

Why are there two horsepower values?
Mechanical horsepower (also called imperial, US, or simply hp) = 745.7 W; metric horsepower (PS, CV, ch) = 735.5 W. Engine names like 100 PS are common in EU brochures; 100 hp in UK/US sources ≈ 101.4 PS, so the difference matters when comparing spec sheets across markets.
How do watts relate to BTU/h?
1 watt = 3.41214 BTU/h. HVAC units quote cooling in BTU/h and electrical draw in W; multiply the input wattage by 3.41 to compare energy-use against cooling-output on the same scale.
Is VA the same as watts?
No — volt-ampere is apparent power (V × A), watts is real power (V × A × power factor). This tool converts real-power units only; if you need to convert VA with a given power factor, scale manually first.
Can I convert calories per second to watts?
Yes. 1 cal/s = 4.184 W (thermochemical calorie by convention). The tool uses this definition; nutrition labels use kcal = 4184 J, so 1 kcal/s = 4.184 kW.
Are my power calculations uploaded?
No. The conversion runs entirely in your browser as static JavaScript. Nothing you enter is sent anywhere; the page works offline after it loads.

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FREE

100% Free

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SIGNUP

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PRIVACY

Private & Secure

Your files never leave your device. All processing is completed locally for maximum privacy.

BATCH

Batch Conversion

Convert multiple files simultaneously to save time. Fast and efficient multi-file queue.

LOCAL

Runs in Browser

Utilizes advanced client-side WebAssembly technology to process files directly inside your tab.

FORMATS

200+ Formats

Supports a wide variety of formats including images, documents, audio, video, and more.

USER REVIEWS

Power Quality Rating

4.8
25 reviews

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