SI Prefixes: How Many Watts in a Kilowatt and Kilowatts in a Megawatt and Vice Versa

SI prefixes are very important in electrical engineering but also in everyday life. Their use is relatively easy, but it can also cause many problems when done incorrectly.

Watts to kilowatts, kilowatts to megawatts, and other conversions are very important when electric energy and power of electric motors, pumps, winches, inverters, batteries, and other devices are being calculated, planned, transferred, or being used. SI prefixes help significantly, especially when dealing with very large or very small values.

Updated: August 31, 2023.

Standard SI Prefixes

SI prefixes are used in order to write down a very large or very small numbers - after all, it is much easier to write, for example, 25 kW than 25000 watts. But, it is also much easier to write 25 MW than 25000 kW or 25000000 watts.

The following chart lists the International System of Units (SI) official prefixes:

Note: the 'Short Scale' is in use in, for example, the United States, while the 'Long Scale' is in use in, for example, Europe.

How Many Watts in a Kilowatt and Kilowatts in a Watt

If you wonder how many watts (W) are there in a kilowatt (kW) and vice versa, just check the chart:

1 kW = 1000W

1W = 10^-3 kW

This is a strictly mathematical 'issue' and can be even continued:

1 kW = 1000W = 1 000 000 mW (milliwatt) = 10⁶ mW = 1 000 000 000 μW (microwatt) = 10⁹ μW

1W = 10^-3 kW = 0.001 kW = 0.000001 MW

It may look confusing, but multiplying large numbers using SI proxies is very simple:

1 kW = 10³ W = 10³ * 10³ mW = 10³⁺³ mW = 10⁶ mW

Or, just use a good calculator and be careful with typing the decimals.

How Many Kilowatts in a Megawatt and Megawatts in a Kilowatt

Similarly, if you want to know how many kilowatts (kW) are there in a megawatt (MW) and vice versa, just check the chart:

1 MW = 1 000 kW = 10³ kW = 10³ * 10³ W = 10³⁺³ W = 10⁶ W = 1 000 000 W

1 kW = 0.001 MW = 10^-3 MW

One kilowatt is a thousand watts, and one megawatt is a thousand kilowatts and/or a million watts.

If You want, You can easily express yottawatts using yoctowatts:

1 YW = 10²⁴ W = 10²⁴ * 10²⁴ yW = 10²⁴⁺²⁴ yW = 10⁴⁸ yW

Why would anybody in real-life electrical engineering use such large or small units, I don't know, but it is a good way of showing the actual scale from one end to another of the SI prefixes chart.

How Many Watts in a Megawatt and Megawatts in a Watt

If you wonder how many watts (W) are there in a Megawatt (MW) nd vice versa, just check the chart:

1 MW = 1 000 kW = 1 000 000 W = 10⁶ W

1W = 0.001 kW = 0.000001 MW = 10^-6 MW

So, one Megawatt is a million Watts, and Watt is a one-millionth of a Megawatt.

How often does one use Megawatts (MW) in real life?

Well, the Rimac Nevera hypercar's maximum power output is 1914 HP, which is ~1.4 MW, and that is 1400000 Watts.

And that is a lot.

Watts to Kilowatts and Kilowatts to Watts Conversion Calculator

To find out power expressed in Watts or kilowatts, feel free to use the following calculator:

One may also use this calculator to convert kilowatts to Megawatts and vice versa, or milliwatts to watts and similar.

Long Story Short: Unit conversions, including W to kW to MW and back, are easy, just be sure to remember the right formulas, for example,

1 MW = 1 000 kW = 1 000 000 W = 1 000 000 000 mW

And don't forget to use the calculator, especially for very large or very small values.