A “prefix” is a word that is placed in front of another word to modify it. An example of a typical prefix would be placing the letters “dis” in front of the word appear. It changes the word from something we can see to something we cannot.
When we measure in the metric system we will often use prefixes to better describe the amounts. We have words to allow the reader to quickly identify how small or large the measurement is.
It’s similar to how we use money. Typically we use $1, $5, or $10 dollar bills to pay for a fast food lunch. If you wanted to use only pennies you could but it would fill the counter with coins. The amount of money is the same regardless of the bills or coins we use to get there. Some prefixes refer to sizes LARGER than the main unit and some prefixes will make the main unit SMALLER in size.
Prefixes that multiply into LARGER units
When we measure something that is LARGER than the meter, liter, or gram we use the following prefixes to modify the units we use:
| prefix | multiplies the base unit by… |
| deka | 10 (ten) |
| hecto | 100 (hundred) 102 |
| kilo | 1000 (thousand) 103 |
| mega | 1,000,000 (million) 106 |
| giga | 1,000,000,000 (billion) 109 |
| tera | 1,000,000,000,000 (trillion) 1012 |
| peta | 1,000,000,000,000 (quadrillion) 1015 |
| exa | 1,000,000,000,000,000 (quintillion) 1018 |
“deka” (deca) – multiplies the unit by TEN (10)
| unit | equal to | in the real world |
| dekameter | 10 meters | width of a classroom |
| dekaliter | 10 liters | backpack |
| dekagram | 10 grams | a pen |
| dekaNewton | 10 Newtons | a baseball bat |
“hecto” – multiplies the unit by one HUNDRED (100)
| unit | equal to | in the real world |
| hectometer | 100 meters | almost a full football field between goalposts |
| hectoliter | 100 liters | mini-fridge |
| hectogram | 100 grams | gaming mouse |
| hectoNewton | 100 Newtons | medium sized dumbbell |
“kilo”- multiplies the unit by one THOUSAND or 1X103 (1000)
| unit | equal to | in the real world |
| kilometer | 1000 meters | The walk around the lake at the EPCOT center |
| kiloliter | 1000 liters | hot tub |
| kilogram | 1000 grams | a phone-sized amount of Gold |
| kiloNewton | 1000 Newtons | average weight of a pro football player |
| kilobyte | 1000 bytes of data | While not “officially” metric, the prefixes have been adopted to express the amount of stored or usable computer information space. 1kb of information is about a half page of text in a word processing program. |
“mega”- multiplies the unit by one MILLION or 1X106 (1,000,000)
| unit | equal to | in the real world |
| Megameter | 1million meters | the distance from St. Louis to Dallas |
| Megaliter | 1million liters | your local water tank |
| Megagram | 1million grams | mass of a Clydesdale |
| MegaNewton | 1million Newtons | weight of a Blue whale |
| Megabyte | 1 million bytes of data | 1 Mb of data is about 1 minute of mp3 audio or a picture that is 1024 x 1024 |
“giga”- multiplies the unit by one BILLION or 1X109 (1,000,000,000)
| unit | equal to | in the real world |
| gigameter | 1billion meters | roughly the distance from Moon to the James Webb orbital telescope NASA |
| gigaliter | 1billion liters | The volume of water in the Caspian Sea |
| gigagram | 1 billion grams | mass of Gold the size of a 4 meter boulder |
| gigaNewton | 1 billion Newtons | the weight of a cruise ship |
| gigabyte | 1 billion bytes of data | About 1 HOUR of high quality video |
“tera”- multiplies the unit by one TRILLION or 1X1012 (1,000,000,000,000)
| unit | equal to | in the real world |
| terameter | 1 trillion meters | the distance from |
| teraliter | 1 trillion liters | |
| teragram | 1 trillion grams | mass of |
| teraNewton | 1 trillion Newtons | weight of |
| terabyte | “1 trillion” bytes | close to 250 feature-length movies |
“exa”- multiplies the unit by one QUADRILLION or 1X1015 (1,000,000,000,000,000)
| unit | equal to | in the real world |
| exameter | 1 quadrillion meters | the distance from |
| exaliter | 1 quadrillion liters | |
| exagram | 1 quadrillion grams | mass of |
| exaNewton | 1 quadrillion Newtons | weight of |
| exabyte | “1 quadrillion” bytes |
Prefixes that divide into SMALLER units
We will now use words that make the basic unit smaller in size. Placing the prefix “deci” in front of a unit means that we are referring to 1/10th of that unit. A decimeter is one tenth of the distance that a meter is. This means we will need 10 decimeters to be the same distance as one meter. “Deci” can be placed in front of any unit to change its size by a tenth.
Now let’s divide decimeter into ten equal parts. This is called a centimeter. Notice that we have changed the prefix to “centi” which means ONE HUNDRETH of the main unit. ONE centimeter is ONE HUNDREDTH of a meter stick. There are 100 cents in a dollar, 100 years in a century, and a Roman Centurion was in charge of 100 soldiers.
Below is a demonstration of what things look like as you get smaller and smaller by factors of 10, and then by factors of 1000.
| prefix | multiplies the base unit by… |
| deci | 0.1 (one tenth) 10-1 |
| centi | 0.01 (one hundredth) 10-2 |
| milli | 0.001 (one thousandth) 10-3 |
| micro | 0.000001 (one millionth) 10-6 |
| nano | 0.000000001 (one billionth) 10-9 |
| pico | 0.000000000001 (one trillionth ) 10-12 |
| femto | 0.000000000001 (one quadrillionth) 10-15 |
| atto | 0.000000000000001 (one quintillionth) 10-18 |
“deci” – multiplies the unit by one TENTH or 1 X 10-1
| unit | equal to | in the real world |
| decimeter | 0.1 meters 1/10 of a meter | |
| deciliter | 0.1 liters 1/10 of a liter | |
| decigram | 0.1 grams 1/10 of a gram | |
| deciNewton | 0.1 Newtons 1/10 of a Newton |
“centi” – multiplies the unit by one HUNDREDTH or 1 X 10-2
| unit | equal to | in the real world |
| centimeter | 0.01 meters | |
| centiliter | 0.01 liters | |
| centigram | 0.01 grams | |
| centiNewton | 0.01 Newtons |
“milli” – multiplies the unit by one THOUSANDTH or 1 X 10-3
| unit | equal to | in the real world |
| millimeter | 0.001 meters | |
| milliliter | 0.001 liters | |
| milligram | 0.001 grams | |
| milliNewton | 0.001 Newtons |
“micro” – multiplies the unit by one MILLIONTH or 1 X 10-6
| unit | equal to | in the real world |
| micrometer | 0.000001 meters | |
| microliter | 0.000001 liters | |
| microgram | 0.000001 grams | |
| microNewton | 0.000001 Newtons |
“nano” – multiplies the unit by one BILLIONTH or 1 X 10-9
| unit | equal to | in the real world |
| nanometer | 0.000000001 meters | |
| nanoliter | 0.000000001 liters | |
| nanogram | 0.000000001 grams | |
| nanoNewton | 0.000000001 Newtons |
“pico” – multiplies the unit by one TRILLIONTH or 1 X 10-12
| unit | equal to | in the real world |
| picometer | 0.000000000001 meters | |
| picoliter | 0.000000000001 liters | |
| picogram | 0.000000000001 grams | |
| picoNewton | 0.000000000001 Newtons |
“femto” – multiplies the unit by one QUADRILLIONTH or 1 X 10-15
| unit | equal to | in the real world |
| femtometer | 0.000000000000001 meters | |
| femtoliter | 0.000000000000001 liters | |
| femtogram | 0.000000000000001 grams | |
| femtoNewton | 0.000000000000001 Newtons |
“atto” – multiplies the unit by one PENTILLIONTH or 1 X 10-6
| unit | equal to | in the real world |
| attometer | 0.000000000000000001 meters | |
| attoliter | 0.000000000000000001 liters | |
| attogram | 0.000000000000000001 grams | |
| attoNewton | 0.000000000000000001 Newtons |