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Watt, kW, PS, HP and more
This power converter instantly converts between watts, kilowatts, metric horsepower (PS), mechanical horsepower (HP), and more. Conversions are based on fixed international factors — for example, 1 HP equals exactly 745.7 watts. Just enter any value and all other units update immediately.
1 Watt equals 0.001 Kilowatt. The full conversion table for all 7 units is right below the calculator.
| Unit | W | kW | MW | hp | PS | BTUh | kcalh |
|---|---|---|---|---|---|---|---|
| 1 Watt | 1 | 0.001 | 1.0000e-6 | 0.001341 | 0.00136 | 3.412142 | 0.859845 |
| 1 Kilowatt | 1000 | 1 | 0.001 | 1.341022 | 1.359621 | 3412.14245 | 859.845228 |
| 1 Megawatt | 1000000 | 1000 | 1 | 1341.021859 | 1359.621155 | 3412142.450123 | 859845.227859 |
| 1 Horsepower (HP) | 745.7 | 0.7457 | 0.000746 | 1 | 1.013869 | 2544.434625 | 641.186586 |
| 1 Metric horsepower (PS) | 735.499 | 0.735499 | 0.000735 | 0.98632 | 1 | 2509.62736 | 632.415305 |
| 1 BTU/hour | 0.293071 | 0.000293 | 2.9307e-7 | 0.000393 | 0.000398 | 1 | 0.251996 |
| 1 kcal/hour | 1.163 | 0.001163 | 1.1630e-6 | 0.00156 | 0.001581 | 3.968322 | 1 |
Rounded to six significant digits.
A power converter changes electrical energy from one form to another — for example alternating current to direct current, or one voltage level to another. In the context of units, converting power means expressing the same amount of energy per second in a different unit, such as watts, kilowatts or horsepower.
An inverter turns direct current into alternating current, while "converter" is the broader term for any device that changes the form of electrical power, most often AC to DC. In everyday use, a converter steps voltage up or down or rectifies it; an inverter is the specific device that produces mains-style AC from a battery.
The best choice is a dual-purpose travel converter with interchangeable plug adapters and a wattage rating above the draw of the device you plan to use. Check whether your appliance already accepts the full international voltage range — if it does, you only need a plug adapter, not a converter.
Its purpose is to make an electrical supply usable by a device that needs a different voltage, current type or frequency. Without it, equipment designed for one supply would either not run or be damaged.
You only need an adapter if your device's label lists a voltage range covering the country you're visiting; an adapter changes only the plug shape. If the device is built for a single voltage that doesn't match the local mains, you need a converter or transformer as well.
The two basic types are AC-DC converters (rectifiers), which turn alternating current into direct current, and DC-DC converters, which change one DC voltage into another. Step-up (boost) and step-down (buck) are the two directions a DC-DC converter can work in.
The main families are AC-DC (rectifier), DC-AC (inverter), DC-DC (buck, boost, buck-boost) and AC-AC converters such as transformers and cycloconverters. Each is defined by the type of current going in and coming out.
A transformer changes AC voltage using magnetic coupling and always keeps the current as AC, whereas a converter can also change the current type, for example AC to DC. Transformers are therefore one specific kind of power conversion device, not a substitute for every converter.
Common designs are linear transformer-based units, switch-mode (SMPS) converters, and multi-stage converter-chargers used in RVs and boats. Switch-mode types are lighter and more efficient, while linear units are simpler and produce less electrical noise.
Whether you're comparing car engines, planning a solar installation, or working on an engineering project, understanding and converting units of power is an essential skill. Our free Power Converter at simple-calculator.online makes it effortless to switch between watts, kilowatts, horsepower, PS, and many other units in a matter of seconds.
Our power converter covers all the major units used in engineering, automotive, and energy sectors worldwide:
This comprehensive range of units makes the tool indispensable for engineers, students, mechanics, and anyone working across international standards.
Using the converter couldn't be simpler. Enter your value, select the source unit, pick the target unit, and the result appears instantly – no formulas needed, no manual calculations required.
One of the most common reasons people use a power converter is to compare car engine outputs. For example, a vehicle rated at 300 HP (as commonly listed in US specs) equals approximately 223.7 kW or 304.3 PS. When browsing European or Japanese car specifications, the PS figure is often listed, which can confuse buyers used to HP ratings. Our converter bridges that gap instantly.
In renewable energy, power is almost always expressed in kilowatts (kW) or megawatts (MW). A residential solar panel system might be rated at 6 kW, which equals 6,000 W or roughly 8.2 HP. Engineers and homeowners often need to cross-reference these figures with older equipment specifications or international standards, making a reliable converter invaluable.
Air conditioning units in the United States are rated in BTU/h, while European equivalents use kilowatts. A typical 12,000 BTU/h air conditioner equals approximately 3.5 kW – a conversion that's critical when purchasing international HVAC equipment or comparing energy efficiency ratings.
Electric motors and industrial equipment specifications can vary widely depending on the country of manufacture. Older British machinery may list power in imperial HP, while modern European equipment uses kW. The ability to convert between these quickly prevents costly specification errors on the job site.
Power is the rate at which energy is transferred or converted, expressed by the formula P = E / t (Power = Energy divided by Time). Historically, different regions and industries developed their own measurement systems. The UK and US adopted the imperial system with HP and BTU, while Europe adopted the metric system with watts and PS. Today, the International System of Units (SI) recognizes the watt as the standard, but legacy units remain in widespread use.
Understanding these differences isn't just academic – it has real financial and safety implications. Specifying the wrong motor power in an industrial installation, for example, can lead to equipment failure or safety hazards. A reliable unit converter minimizes this risk.
One mechanical horsepower (HP) equals 745.7 watts. This is the standard used in the United States. Metric horsepower (PS), used in Europe, equals 735.5 watts – slightly less than the imperial HP.
HP (horsepower) is the imperial unit equal to 745.7 W, while PS (Pferdestärke) is the metric unit equal to 735.5 W. The difference is about 1.4%, which matters when comparing high-performance engine specs across regions.
To convert kilowatts to horsepower, multiply the kW value by 1.341. For example, 100 kW × 1.341 = 134.1 HP. Our converter handles this automatically, saving you the manual calculation.
Yes, absolutely. The power converter on simple-calculator.online is completely free, requires no registration, and works on any device – desktop, tablet, or smartphone.
Yes. While this tool focuses on unit conversion rather than full circuit analysis, it is highly useful for converting between watts, kilowatts, and megawatts in electrical engineering contexts, such as calculating generator capacity or motor specifications.