Power Converter
Convert between power units — milliwatts, watts, kilowatts, megawatts, horsepower, metric horsepower and BTU per hour. Free instant converter.
About power conversions
Power is the rate at which energy is used or produced, measured in watts — one joule per second. The metric units step in powers of 1,000 from milliwatts up to megawatts, so conversions inside the metric system are exact and lose nothing to rounding.
Horsepower is the exception, and there are two of them. Mechanical horsepower (hp), used in the United States and UK, is 745.7 watts; metric horsepower (PS), used for vehicle engines across much of Europe and Asia, is 735.49875 watts. The same engine therefore carries a larger number in hp than in PS. BTU per hour is the unit for heating and cooling capacity, where 12,000 BTU/h is roughly 3.5 kW.
- Appliance, generator and inverter ratings (watts, kilowatts).
- Vehicle engine output (horsepower or metric horsepower).
- Solar panels and batteries (watts, kilowatts).
- Air conditioning and heating (BTU per hour).
Reading the answers. Metric power conversions are exact. Check whether a horsepower figure is mechanical or metric before comparing two engines.
The units in this converter
What each unit is and where it is normally used. Everything here is converted through the watts.
- Milliwatts (mW)
- A milliwatt is one thousandth of a watt. It is used for small electronics, radio transmission power and laser pointers; an indicator LED draws a few milliwatts.
- Watts (W)
- The watt is the SI unit of power: one joule per second. It is used for light bulbs, small appliances and solar panel ratings; an LED bulb is typically 5 to 15 watts.
- Kilowatts (kW)
- A kilowatt is 1,000 watts. It is the usual unit for appliance ratings, generators, inverters and household electricity demand.
- Megawatts (MW)
- A megawatt is 1,000 kilowatts. It is used for power stations, industrial loads and grid capacity, where large generator sets run into the megawatts.
- Horsepower (mechanical) (hp)
- Mechanical horsepower is 745.7 watts, the unit used for engine and motor output in the United States and UK. It is a different size from metric horsepower.
- Metric horsepower (PS)
- Metric horsepower (PS) is 735.49875 watts, used for vehicle engine ratings across much of Europe and Asia. It is slightly smaller than mechanical horsepower.
- BTU per hour (BTU/h)
- One BTU per hour is 0.29307107 watts. It is used for air-conditioning and heating capacity, where '12,000 BTU' means roughly 3.5 kW.
Tanzania reference points
Real quantities in power, shown in the units people actually use.
Tanzania's installed electricity generation capacity
2,881.332 MW · 2,881,332,000,000 mW · 2,881,332,000 W · 2,881,332 kW · 3,863,929.859457 hp · 3,917,521.273829 PS · 9,831,512,881.841255 BTU/h
EWURA reports 2,842.96 MW on the main grid and 38.372 MW off-grid, with TANESCO holding 92.31% of it. Installed capacity is what the country could generate at once, not what it generates on an average day.
Source: EWURA Fact Sheet — electricity sub-sector (installed capacity) · verified 2026-09-14
Popular conversions
Convert from any power unit
Each unit has its own page with every other unit in the dimension, the exact factor for each, and worked values.
Frequently asked questions
How many watts are in a horsepower?
One mechanical horsepower equals about 745.7 watts.
How do I convert kilowatts to horsepower?
Multiply kilowatts by about 1.341 to get horsepower (1 kW ≈ 1.341 hp).
What is a BTU per hour?
BTU per hour is a measure of heating/cooling power; 1 BTU/h equals about 0.293 watts.
All power conversions
Every power conversion on Calculator, listed in full.
- Milliwatts to Watts
- Milliwatts to Kilowatts
- Milliwatts to Megawatts
- Milliwatts to Horsepower (mechanical)
- Milliwatts to Metric horsepower
- Milliwatts to BTU per hour
- Watts to Milliwatts
- Watts to Kilowatts
- Watts to Megawatts
- Watts to Horsepower (mechanical)
- Watts to Metric horsepower
- Watts to BTU per hour
- Kilowatts to Milliwatts
- Kilowatts to Watts
- Kilowatts to Megawatts
- Kilowatts to Horsepower (mechanical)
- Kilowatts to Metric horsepower
- Kilowatts to BTU per hour
- Megawatts to Milliwatts
- Megawatts to Watts
- Megawatts to Kilowatts
- Megawatts to Horsepower (mechanical)
- Megawatts to Metric horsepower
- Megawatts to BTU per hour
- Horsepower (mechanical) to Milliwatts
- Horsepower (mechanical) to Watts
- Horsepower (mechanical) to Kilowatts
- Horsepower (mechanical) to Megawatts
- Horsepower (mechanical) to Metric horsepower
- Horsepower (mechanical) to BTU per hour
- Metric horsepower to Milliwatts
- Metric horsepower to Watts
- Metric horsepower to Kilowatts
- Metric horsepower to Megawatts
- Metric horsepower to Horsepower (mechanical)
- Metric horsepower to BTU per hour
- BTU per hour to Milliwatts
- BTU per hour to Watts
- BTU per hour to Kilowatts
- BTU per hour to Megawatts
- BTU per hour to Horsepower (mechanical)
- BTU per hour to Metric horsepower
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