Power Converter

Convert between all common power units including watts, kilowatts, megawatts, horsepower (imperial and metric), BTU/hour, and calorie/second.

Power Converter 11 units

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Common Power Conversions

All Power Conversions

Browse all unit combinations — each page has a dedicated converter and conversion table.

Watts → Milliwatts Watts → Kilowatts Watts → Megawatts Watts → Gigawatts Watts → Horsepower Watts → Metric HP Watts → BTU/hour Watts → BTU/minute Watts → kcal/hour Watts → ft·lb/s Milliwatts → Watts Milliwatts → Kilowatts Milliwatts → Megawatts Milliwatts → Gigawatts Milliwatts → Horsepower Milliwatts → Metric HP Milliwatts → BTU/hour Milliwatts → BTU/minute Milliwatts → kcal/hour Milliwatts → ft·lb/s Kilowatts → Watts Kilowatts → Milliwatts Kilowatts → Megawatts Kilowatts → Gigawatts Kilowatts → Horsepower Kilowatts → Metric HP Kilowatts → BTU/hour Kilowatts → BTU/minute Kilowatts → kcal/hour Kilowatts → ft·lb/s Megawatts → Watts Megawatts → Milliwatts Megawatts → Kilowatts Megawatts → Gigawatts Megawatts → Horsepower Megawatts → Metric HP Megawatts → BTU/hour Megawatts → BTU/minute Megawatts → kcal/hour Megawatts → ft·lb/s Gigawatts → Watts Gigawatts → Milliwatts Gigawatts → Kilowatts Gigawatts → Megawatts Gigawatts → Horsepower Gigawatts → Metric HP Gigawatts → BTU/hour Gigawatts → BTU/minute Gigawatts → kcal/hour Gigawatts → ft·lb/s Horsepower → Watts Horsepower → Milliwatts Horsepower → Kilowatts Horsepower → Megawatts Horsepower → Gigawatts Horsepower → Metric HP Horsepower → BTU/hour Horsepower → BTU/minute Horsepower → kcal/hour Horsepower → ft·lb/s Metric HP → Watts Metric HP → Milliwatts Metric HP → Kilowatts Metric HP → Megawatts Metric HP → Gigawatts Metric HP → Horsepower Metric HP → BTU/hour Metric HP → BTU/minute Metric HP → kcal/hour Metric HP → ft·lb/s BTU/hour → Watts BTU/hour → Milliwatts BTU/hour → Kilowatts BTU/hour → Megawatts BTU/hour → Gigawatts BTU/hour → Horsepower BTU/hour → Metric HP BTU/hour → BTU/minute BTU/hour → kcal/hour BTU/hour → ft·lb/s BTU/minute → Watts BTU/minute → Milliwatts BTU/minute → Kilowatts BTU/minute → Megawatts BTU/minute → Gigawatts BTU/minute → Horsepower BTU/minute → Metric HP BTU/minute → BTU/hour BTU/minute → kcal/hour BTU/minute → ft·lb/s kcal/hour → Watts kcal/hour → Milliwatts kcal/hour → Kilowatts kcal/hour → Megawatts kcal/hour → Gigawatts kcal/hour → Horsepower kcal/hour → Metric HP kcal/hour → BTU/hour kcal/hour → BTU/minute kcal/hour → ft·lb/s ft·lb/s → Watts ft·lb/s → Milliwatts ft·lb/s → Kilowatts ft·lb/s → Megawatts ft·lb/s → Gigawatts ft·lb/s → Horsepower ft·lb/s → Metric HP ft·lb/s → BTU/hour ft·lb/s → BTU/minute ft·lb/s → kcal/hour

📐 How to Use

Choose your starting unit in the From dropdown and your target in the To dropdown; both lists carry all 11 power units.
Enter a number in the From field. The To field and the result line below it update as you type, and the formula line states the one-unit ratio.
Press the swap button between the dropdowns to reverse the direction, then use Copy to put the figure on your clipboard.
Click a card in Common Power Conversions to load that pair with a value of 1, or follow a link in All Power Conversions for a dedicated page with a full conversion table.

❓ Frequently Asked Questions

QHow many watts are in 1 gigawatt?

One gigawatt is 1,000,000,000 watts. It is also 1,000,000 kilowatts and 1,000 megawatts, because each SI prefix step multiplies by a thousand. Gigawatts describe power station output and national grid capacity, not individual machines, where kilowatts are the usual scale.

QWhat is 1 kilowatt in horsepower?

1 kilowatt is 1.341022 horsepower, using imperial horsepower of 745.6999 watts. The same kilowatt is 1.359622 metric horsepower. European manufacturers normally quote PS, so a specification sheet can show two different numbers for one engine.

QWhat is the difference between hp and PS?

Imperial horsepower equals 550 foot-pounds per second, taken here as 745.6999 watts, while metric horsepower equals 75 kilogram-force meters per second, or 735.4988 watts. PS is the smaller unit, so the same engine scores about 1.4 percent more PS than hp.

QHow do I convert kilowatts to BTU per hour?

Multiply by 3412.1425: one kilowatt is 3412.1425 BTU per hour, and one watt is 3.412142 BTU/hr. Air conditioners and boilers are rated in BTU/hr in the United States, so this pair comes up whenever a heating load is quoted in watts.

ℹ️ About Power Conversion

Power is the rate at which energy moves: one watt is one joule per second. Converting it is awkward because three traditions overlap, the SI watt from physics, horsepower from eighteenth-century steam engine salesmanship, and BTU per hour from American heating and cooling. Horsepower itself splits in two. Imperial, or mechanical, horsepower is 550 foot-pounds per second, about 745.7 watts; metric horsepower, written PS, is 75 kilogram-force meters per second, or 735.5 watts. An engine rated 100 PS is weaker than one rated 100 hp.

This converter holds 11 units and runs every conversion through the watt, multiplying by the source unit's watt factor and dividing by the target's. Results keep four decimal places for figures of ten and above and up to eight below one, with trailing zeros dropped. The arithmetic happens in your browser as you type.

📏 11 Supported Units

Watt (W), Milliwatt (mW), Kilowatt (kW), Megawatt (MW), Gigawatt (GW), Horsepower (imp) (hp), Horsepower (met) (PS), BTU/hour (BTU/hr), BTU/minute (BTU/min), kcal/hour (kcal/h), ft·lb/s (ft·lb/s).