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.

Two tape measures, one in mm, the other in cm

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.


1 meter = 100 centimeters

The length of this guitar is about 1 meter

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

The back of this kitchen chair is 1meter


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.