# How long is a centimeter on a ruler?

**How long is a centimeter on a ruler?** How to identify a cm on a ruler? How does the relationship between a centimeter and other units of length, which you can see on a ruler look? If you are looking for the answers to these questions, you are in the right place. We are going to dispel all your doubts and explain the topic of the length of a cm on a ruler clearly.

**How big is a centimeter on a ruler? **It is one of the commonly asked questions by people who just started using this measurement tool, especially children and teenagers, and also by those who used this tool such a long time ago that they need a reminder now.

Regardless of in which group you are, you will find an exact answer to the question of how long is a centimeter on a ruler in this article. We are going to explain it to you step by step with practical examples too. So let’s start.

## Where is a centimeter on a ruler?

To know how long a centimeter on a ruler is, it is needed to know where a cm on a ruler is first. That’s why we have started with this issue.

**A centimeter on a ruler is always marked in a special way.** The main way to mark a centimeter on a ruler is using a longer line. Sometimes this line can also be in bold. Rarely it can be also marked by using another, distinctive color.

Which line is a centimeter on a ruler? If we have to answer that question succinctly and sum up the previous paragraph, we will say that it will be the most distinctive line. And to be more precise, the line of 1 cm will always be the tenth line from the left side.

Be careful if you use a ruler with both centimeters and inches. Then the line of a centimeter will be on the opposite side of the side where are marked inches.

So the basic information is behind us. Now it is time for the main part of the article and to know how long a centimeter is on a ruler. Let’s move on!

## How long is 1 cm on a ruler – millimeters

A centimeter on a ruler is always shown as composed of millimeters. It is the basic way to know the length of 1 cm. But how long is a centimeter on a ruler exactly when it comes to millimeters?

To know the answer to that question, it is needed to know how many millimeters are in a centimeter.

So have a look at the relationship between a centimeter and millimeters:

- 1 centimeter = 10 millimeters.

So a centimeter is 10 millimeters long. How does it refer to a ruler?

If you read the previous part carefully, you should note that we said a centimeter is always the tenth line from the left side on a ruler.

And that’s the answer – **a centimeter is 10 millimeters long on a ruler**, which means 1 centimeter is the tenth line from the left side on a ruler.

We are sure that now this issue is clear for you. But what about the length of a centimeter on a ruler in comparison to inches? Let’s check it too.

## How long is a cm on a ruler – inches

Most rulers have only marked centimeters and millimeters. But there are also these, which have inches on the opposite side marked. How long is a cm on a ruler then?

To know how much is a centimeter on a ruler when it comes to inches, it is needed to know how many inches are in a centimeter.

So let’s have a look at the equation: 1 centimeter = 1/2.54 inches ≈ 0.3937 inches.

**So how long is a cm on a ruler when it comes to inches? **You can identify a centimeter approximately in 0.4 part of the length of an inch on a ruler.

Of course, a calculation like that is not commonly used. We showed this comparison to you as a tidbit mostly. The most important thing for you when it comes to a ruler and a centimeter is to know the information from the previous part of the article.

So if the topic of how long is 1 centimeter on a ruler is behind us, what about using this knowledge in practice? Let’s make some calculations!

## How long is 3 cm on a ruler?

To answer that question, the information which we gave you above about how long is a centimeter on a ruler will be needed. We are going to show you 2 equations that will allow you to calculate how long is any number of centimeters on a ruler.

But first, a quick reminder of how many millimeters in a centimeter on a ruler: 1 centimeter = 10 millimeters.

So how long is 3 cm on a ruler? If 1 cm on a ruler is equal to 10 millimeters, you need to multiply 10 millimeters by another number of centimeters, in this case 3. The equation will look as follows:

3 centimeters * 10 millimeters = 30 millimeters

But what about 3 cm on a ruler in comparison to inches? Let’s see.

Here is a reminder of how many centimeters are in an inch on a ruler: 1 centimeter ≈ 0.3937 inches ≈ 0.4 inches.

We rounded off this approximation to one decimal place to make your calculation as easy as possible. If you want to get a more appropriate result, you can use the longer version of approximation. The scheme to calculate how long 3 cm is on a ruler when it comes to inches will be the same, regardless of which conversion rate you will use.

So how to calculate 3 cm to inches on a ruler? We will be based on the equation given above, but this time we will change millimeters to inches in it. How does it look after this little change?

3 centimeters * 0.4 inches = 1.2 inches

As you can see, both these calculations are not complicated. We are sure that you understand the process. To make it maximally clear, we prepared 2 additional examples for you. Let’s see them.

## How long is 12 cm in ruler?

This example will be a little bit more difficult. Why? The higher the number, the more calculations to make. But don’t worry – we are sure you can make it almost with the same easiness as in the previous example.

So let’s see how long 12 cm in ruler is in millimeters first. As you remember, you need to multiply the number of centimeters by 10 millimeters.

The calculations will look like these:

12 centimeters * 10 millimeters = 120 millimeters

And what about inches? Let’s calculate it too.

This time we are going to multiply the number of centimeters by 0.4 inches. So the calculations look as follows:

12 centimeters * 0.4 inches = 4.8 inches

And the calculations are behind us. Was it difficult? We are sure that the answer is no, as we promised you.

Are you ready for the last example? See it down below.

## How long is 22 cm on a ruler?

The last example will require the most calculations. In this part, we are going to check how long 22 cm on a ruler is. Of course, in 2 ways, as in the previous examples. So let’s start.

First, check how long 22 cm on a ruler is when it comes to millimeters. Multiply 22 centimeters by 10 millimeters to get the result.

The calculations look like these:

22 centimeters * 10 millimeters = 220 millimeters

And how does the result look when it comes to inches? Let’s see. This time multiply 22 cm by 0.4 in.

The equation will look as follows:

22 centimeters * 0.4 inches = 8.8 inches

And that’s the end of the practical part. We are sure that after seeing these 3 step by step examples you can calculate any number of centimeters on a ruler to millimeters or inches (depending on what you need) without any problems.

## How long is a centimeter on a tape measure?

This whole article is dedicated to a ruler, but as a bonus, we added a part dedicated to a tape measure.

What do you think – how long is a centimeter on a tape measure? Is there any difference between a centimeter on a ruler and a tape measure? We hurry up with explanations.

One thing you need to remember – **a centimeter is always the same, regardless of whether it is on a ruler or a tape measure**.

So why do we raise the issue of a tape measure at all? **A centimeter on a tape measure can be defined in 2 more ways than a centimeter on a ruler. **On a ruler, the biggest unit of length is a centimeter or inch (depending on which type of ruler you use). On a tape measure, the biggest unit is a meter of feet (depending on the type of tape measure too).

So how long is a centimeter when it comes to meters? The equation is down below, have a look:

- 1 centimeter = 0.01 (1/100) meters.

As you can see, a centimeter is quite small in comparison to a meter.

And what about a length of a centimeter when it comes to feet? Let’s check it:

- 1 centimeter = 25/64 feet ≈ 0.032808399 feet.

And in this comparison also a centimeter is a smaller unit.

In the end, we gathered all ways to define a centimeter on a tape measure in one place. Let’s see it.

How long is a centimeter on a tape measure?

1 centimeter | 10 millimeters |

1 centimeter | 1/2.54 ≈ 0.3937 inches |

1 centimeter | 0.01 meters |

1 centimeter | 25/64 ≈ 0.032808399 feet |

We hope that this knowledge of how long a centimeter on a tape measure is will be also useful for you.

### How long is a centimeter on a ruler – summary

We are coming to the end of this article. The last thing which we want to show you is a summary. We know that things that are said at the end are better remembered, so we prepared for you the 3 most important pieces of information (in a nutshell, of course), which you should know after reading this article.

Have a look at our little FAQ section:

- Which line is a centimeter on a ruler? A centimeter is the tenth line from the left side of a ruler.
- How long is a centimeter on a ruler in millimeters? A centimeter is 10 millimeters long on a ruler.
- How long is a cm on a ruler in inches? A centimeter is 1/2.54 inches (about 0.3937) long on a ruler.

We hope that this math issue is so much easier for you now! You have learned how to use a ruler without any troubles. And not only – you have seen how to use this knowledge in practice to make some conversion, for instance, to check how long is 3 cm on a ruler.

Do you want to know more about centimeters conversion? Check **how do you calculate cm to inches **effortlessly.