These are the most common measurements:

Small units of length are called millimeters.
A millimeter is about the thickness of a plastic id card (or credit card).
Or about the thickness of 10 sheets of paper on top of each other.
This is a very small measurement!

When we have 10 millimeters, it can be called a centimeter.
1 centimeter = 10 millimeters
A fingernail is about one centimeter wide.

We can use millimeters or centimeters to measure how tall we are, or how wide a table is, but to measure the length of a football field it is better to use meters.
meter1 meter = 100 centimeters

Meters can be used to measure the length of a house, or the size of a playground.
And because a centimeter is 10 millimeters:
1 meter = 1000 millimeters


A kilometer is equal to 1000 meters.
1 kilometer = 1000 meters
When we need to get from one place to another, we measure the distance using kilometers.
The distance from one city to another or how far a plane travels can be measured using kilometers.
In Summary:

10 millimeters = 1 centimeter
100 centimeters = 1 meter
1000 meters = 1 kilometer
Lots of Examples
A centimeter (cm) is about:
A meter (m) is about:
![]() | One meter is about one long step of an adult man. |
A kilometer (km) is about:
![]() | One kilometer is around a 12 minute walk. |