Metric Prefixes: Lesson for Kids

Instructor: Amanda McCarthy

Amanda has been teaching for ten years and has a master's degree in elementary education.

The metric system is the most widely used measurement system in the world, and it uses prefixes to show different values. Let's learn about the metric system as well as prefixes and what they mean.

What Is the Metric System?

The metric system is a system of measurements that's used in everyday activities and science. Most countries in the world use it as their primary measurement system, except the United States and a few smaller counties. It's also the universal form of measurement for the scientific community--the metric system allows scientists a standard for communicating numbers, making experiments easier to understand and replicate.

Much like the place value chart you learned about in math class, the metric system is a base-10 system, which means it is based on the number 10. When you move one place to the left, the next value is 10 times larger. When you move one place to the right, the value is 10 times lower. Think of it like a staircase:

The metric staircase
Metric Ladder

Metric Prefixes

The metric system uses three standard units:

  • Liters are used to measure liquid volume (how much space liquid takes up).
  • Grams are used to measure mass (how much of an object there is).
  • Meters are used to measure distance (the amount of space from one point to another).

These three standard units are the starting points for the metric system, similar to the ones spot on a place value chart. In order to make these standard units bigger or smaller, we use prefixes. A prefix is a word attached to the front of another word to change its meaning. Now, let's explore the basic metric prefixes:

prefix table

Prefixes That Mean Smaller

Let's start at the basic unit and move downward to the smaller units:

  • Deci: A unit with the prefix deci- means that it is one-tenth the amount of the original unit. So, a decigram is one-tenth of gram. You could turn the 1.0 decigram into a gram by moving the decimal point once to the left (0.1).
  • Centi: A centi- unit is one-hundredth the original unit. So, saying that you have 1.2 centiliters would be the same as saying you have 0.012 liters (the decimal point is moved two to the left).
  • Milli-: When you want to measure the length of something very, very tiny, you use a millimeter. The prefix milli- means one-thousandth. So, a milliliter is one-thousandth of a liter.

As you can see, to move down one step at any point on the metric staircase, you simply divide by 10 (or move the decimal one to the left). That's why it's called a base-10 system!

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account