Kilowatts, Megawatts, Gigawatts: What Do They Mean?

We’ve all seen these expressions, but what do they actually mean? The prefixes are simply multipliers of the unit they describe, grouped in increments of 1,000. 

For example, one kilowatt equals 1,000 watts. This means you could refer to a 1,000-watt heater as a 1-kilowatt heater. Both are different ways of describing the same thing. Decimals work too. 2,700 watts can be stated as 2.7 kilowatts if you prefer. 

Common Prefixes and Their Meanings: 

•  kilo = 1,000 (a thousand times)
•  mega = 1,000,000 (a million times or a thousand thousand times) 
•  giga = 1,000,000,000 (a billion times or a thousand million times) 
•  tera = 1,000,000,000,000 (a trillion times or a thousand billion times) 
•  peta = 1,000,000,000,000,000 (a quadrillion times or a thousand trillion times) 
•  exa = 1,000,000,000,000,000,000 (a quintillion times or a thousand quadrillion times) 
•  zetta = 1,000,000,000,000,000,000,000 (a sextillion times or a thousand quintillion times) 
•  yotta = 1,000,000,000,000,000,000,000,000 (a septillion times or a thousand sextillion times) 
•  ronna = 1,000,000,000,000,000,000,000,000,000 (an octillion times or a thousand septillion times) 
•  quetta = 1,000,000,000,000,000,000,000,000,000,000 (a nonillion times or a thousand octillion times)

As of now, these are the official prefixes that are recognized. Many proposals have come and gone, including some amusing ones like names that sound similar to the Marx brothers. But as of 2022, this is the list. 

Larger Numbers Without Prefixes
Ignoring the prefixes for a moment, what comes next as numbers increase by factors of 1,000? There are names for them too. Starting with nonillion, the list includes:

• decillion 
• undecillion 
•  duodecillion 
•  tredecillion 
•  quattuordecillion 
•  quindecillion 
•  sexdecillion 
•  septendecillion 
•  octodecillion 
•  novemdecillion, 
• and finally vigintillion

That last number equals 1 followed by 63 zeros. 

Real-World Example: Power Plants
To use these prefixes in a real-world context, consider a power station. A generator with a capacity of 100 megawatts (MW) running continuously for 24 hours generates 2,400 megawatt-hours (MWh) of electricity. This can also be stated as 2.4 gigawatt-hours (GWh). Both terms are correct, but when comparing outputs between plants, using the prefix helps make numbers easier to compare. 

A Fun Pop Culture Reference: Back to the Future
In the 1985 movie Back to the Future, Doc Brown is amazed when he watches a video of himself stating that 1.21 gigawatts of power are needed for his invention to work. Marty McFly famously asks, “What the hell is a gigawatt?” They mispronounced it as “jiggawatt,” but we know what they meant. Giga means a billion, so 1.21 gigawatts equals 1,210,000,000 watts. That’s a lot of power, about 1.62 million horsepower! That’s what his flux capacitor was for.* 

Prefixes for Smaller Numbers
Prefixes are also used when numbers get smaller. For example, a thousandth of something is a milli. Shrinking by a factor of 1,000 each time, the list goes like this:

• milli
•  micro 
• nano 
• pico 
• femto 
• atto 
• zepto 
• yocto 
• ronto 
• quecto

Interestingly, some of these prefixes are similar to the ones used for larger numbers, which can make them easier to remember.

Practical Applications
When it comes to electric heaters, these prefixes are used frequently in various contexts:
• Insulation resistance is often measured in the mega-ohm or giga-ohm range. Some testers can even measure up to 1 TΩ (tera-ohms), which is a trillion ohms!
• Test voltage for high-potential testing (hypot testing) is often in the kilovolt range.
• Low resistance measurements use milli-ohm meters, which are highly sensitive and can measure with great precision.
• Leakage current is typically measured in milliamps (mA). For safety, most electrical heaters are designed to keep leakage below 3.0 mA. Some advanced equipment can even measure down to microamps. 

 Prefixes in Everyday Language
These prefixes pop up in our everyday language too. For example:
• Millimeter: A thousandth of a meter.
• Piccolo: A tiny flute (not quite a “pico” flute, but close enough!).
• Megaphone: A device that makes a big noise!
• The Italian phrase “mille grazie” translates to “a thousand thank yous.” 

Fun Fact: MOSFET Transistors
Here’s an interesting bit of trivia using a really large number. The most abundant man-made object in history is the MOSFET (Metal Oxide Semiconductor Field Effect Transistor), used in integrated circuits. Invented in 1959, by 2018 it’s estimated that 13 sextillion MOSFETs had been produced. That’s 13,000,000,000,000,000,000,000! Now that’s a big number. 

Understanding the prefixes like kilo, mega, and giga helps simplify the vast world of measurements, from power generation to everyday terms. Whether discussing massive power outputs or tiny electrical currents, these prefixes make large and small numbers easier to grasp. Their widespread use in science, engineering, and even casual language shows just how essential they are in helping us navigate the complexities of the world around us. So the next time you hear “gigawatt” or “megaphone,” you’ll know exactly what it means!

* You can get your very own flux capacitor from O’Reilly Auto Parts (part number 121g), if they ever get them back in stock again. It must be a hot item. https://www.oreillyauto.com/flux-capacitor