Power Converter

Power unit conversion for watts, kW, MW, horsepower, and BTU/hr

A “power converter” helps you translate power from one unit into another without doing manual math or hunting for reference tables. Power is a rate, meaning how fast energy is being used or produced. Depending on what you are working on, power might be expressed as watts (W), kilowatts (kW), megawatts (MW), horsepower (hp), or even BTU per hour (BTU/hr). The problem is that different industries and products label power differently. This calculator normalizes everything into a consistent set of outputs so you can compare like-for-like.

Use this calculator when you are reading a device label, motor spec sheet, generator rating, HVAC documentation, or an engineering worksheet and need to switch units fast. For example, an electric kettle might be rated at 2,000 W, a solar inverter might be rated in kW, a power station might be quoted in MW, and a motor might be quoted in horsepower. Converting between them is straightforward, but the unit factors are easy to misremember, and a small mistake can create big planning errors.

To use the calculator, enter a power value, choose the unit you are starting from, then select your target unit. You will get a primary converted value plus a quick reference list showing the same power expressed across several common units. That second output is there because many real situations involve checking multiple documents. Seeing the full list makes it harder to misread a spec and easier to sanity-check your numbers.

Assumptions and how to use this calculator

• This converts power units only. It does not convert energy units like kWh, MJ, or BTU (energy), which measure total amount rather than rate.
• Horsepower values use common standard definitions. “hp” here is mechanical horsepower and “PS” is metric horsepower.
• BTU/hr is treated as a power rate. If you have BTU (without “per hour”), that is energy, not power.
• Results are rounded to two decimals for readability. For tight engineering tolerances, keep extra significant figures and verify with your design standard.
• If you are converting device ratings, remember that nameplate power can be “input power” or “output power.” This tool does not correct for efficiency unless the source data already accounts for it.

Common questions

What is the difference between power and energy?

Power is how fast energy is used or produced (a rate). Energy is the total amount used over time. A 2 kW heater running for 3 hours uses 6 kWh of energy. This calculator converts the 2 kW (power), not the 6 kWh (energy).

Why do I see watts on some devices and horsepower on others?

Different industries keep different conventions. Electrical equipment is often labeled in watts or kilowatts. Motors, engines, and some mechanical systems are often labeled in horsepower. The conversion is still valid, but you should confirm whether the rating is continuous, peak, input, or output, because those labels affect decisions more than the unit itself.

Is “hp” the same everywhere?

No. Horsepower has multiple definitions in the real world. This calculator includes mechanical horsepower (hp) and metric horsepower (PS). If a document uses another standard, your number may differ slightly. When accuracy matters, match the standard used in your source document.

What should I do if I only know an approximate value?

Use your best estimate and treat the result as an approximation. The quick reference list is useful here because you can compare the converted values to typical ranges. If you are sizing equipment, add a safety margin and confirm with manufacturer documentation.

Why do my results not match a website that shows more decimal places?

This calculator rounds results to two decimals to keep outputs readable. Rounding can make small differences visible, especially when converting very small or very large values. If you need tighter agreement, use the same unit definitions and rounding rules across your comparisons.