# mm to cm

There are 10 millimeters in 1 centimeter. Both millimeters and centimeters are units of length in the metric system and are related to the meter, the base unit of length in the International System of Units (SI).

## Convert mm to cm

The following converter can convert from millimeters to centimeters or centimeters to millimeters. Just enter a value in either millimeters or centimeters to convert between the two.

### How many mm in a cm

There are 10 millimeters in 1 centimeter, or:

10 mm = 1 cm

### How many cm in a mm

There are 0.1 centimeters in a millimeter, or:

0.1 cm = 1 mm.

## mm to cm conversion

To convert millimeters to centimeters, divide a value in millimeters by 10. To convert centimeters to millimeters, multiply a value in centimeters by 10.

### mm to cm formula

The formula for converting millimeters to centimeters is:

Similarly, to convert centimeters to millimeters, use the formula:

Both millimeters and centimeters are fractions of a meter. "Milli-" comes from the Latin, "mille," meaning one-thousand, and "centi-" comes from "centum" meaning hundred. In the International System of Units, they signify one thousandth and one hundredth respectively.

There are a number of other prefixes in SI aside from centi- and milli-, all of which are used to indicate that a unit is either a multiple or a fraction of a power of 10 of the base unit. We can see this relationship by rewriting the relationship between 1 meter and its corresponding number of centimeters and millimeters:

1 m = 100 cm = 1000 mm

or

1 × 10^{0} m = 1 × 10^{2} cm = 1 × 10^{3} mm

From this we can see that all of these units are related by a power of 10. Thus, to convert from mm to cm (or any other multiple/fraction of a meter), we just need to know what power of 10 the prefix represents, and either multiply or divide, depending whether the prefix indicates that the unit is larger or smaller than the base unit.

Below are some mm to cm conversion examples:

Examples

1. Convert 1828.8 mm to cm:

1828.8 mm ÷ 10 = 182.88 cm

2. Convert 22.7 cm to mm:

22.7 cm × 10 = 227 mm

## What is a millimeter

A millimeter is a measurement of length in the International System of Units (SI).

### Definition of a millimeter

A millimeter is defined as one-thousandth of a meter. The meter is the base unit of length in the International System of Units. It is defined as the length of the path traveled by the speed of light in vacuum in of a second.

### History of the millimeter

The history of the millimeter is based on that of the meter and the metric system. The metric system was introduced in France in 1795 to replace past systems of measurements that were less practical. The definition of the millimeter has consistently been one-thousandth of a meter, but the definition of the meter has changed throughout the course of history with the goal of creating a more robust unit of measurement. For example, in 1899, the definition of the meter was based on a physical prototype named the International Prototype Meter. Although it was made of a combination of platinum and iridium, which is not prone to much fluctuation, it was still an imperfect measure subject to change. For this reason, the meter has since been redefined a few more times to instead be based on physical constants, reducing uncertainty in the definition of the meter.

### Millimeter usage

The millimeter is used widely throughout the world. Usually, it is used for very small, but still visible measurements. Examples include the thickness of paper, a penny, needle, etc. Even though the United States has not officially adopted SI, the millimeter is still used throughout the US in many contexts.

## What is a centimeter

A centimeter is a measurement of length in the International System of Units.

### Definition of a centimeter

A centimeter is defined as one-thousandth of a meter.

### History of the centimeter

The centimeter, like the millimeter, was introduced along with the metric system. Its definition relative to the meter has remained constant (one-hundredth of a meter), but its basis has changed along with that of the meter throughout the course of history, as described in the "history of the millimeter" section above.

### Centimeter usage

The centimeter is used throughout the world. One of the most common uses of the centimeter is its use for the measurement of height. Most countries around the world measure height in centimeters (or meters) with the exception of countries that have not officially adopted the International System of Units, such as the United States. The United States measures height in terms of feet and inches instead.

## Millimeter to centimeter conversion table

The table below shows some common mm to cm conversions:

Millimeter | Centimeter |
---|---|

0.1 | 0.01 |

1 | 0.1 |

10 | 1 |

20 | 2 |

30 | 3 |

50 | 5 |

100 | 10 |

200 | 20 |

500 | 50 |

1,000 | 100 |

10,000 | 1,000 |

## Difference between mm and cm

Millimeters and centimeters differ only in size. They are both measurements of length in SI that are defined relative to the meter, the base unit of length. A millimeter is one-thousandth of a meter while a centimeter is one-hundredth of a meter. Aside from this, millimeters and centimeters mostly differ in how they are used. Both are used to measure relatively small objects, but millimeters are used for smaller objects.