# Centimetre

A **centimetre** (the American spelling is **centimeter**, symbol **cm**) is a unit of length in the International System of Units (SI) measurement system. It is equal to one hundredth of a metre. Centi- is placed in front to say 'a hundredth'. The centimetre is the base unit of length in the old centimetre-gram-second (CGS) system of units.

The centimetre is usually used to measure things that are too big for millimetres but too small for metres. A centimetre is close to the length of a fingernail.

## Contents

## Similarities to other units of length

1 centimetre is *equal* to:

- 10 millimetres
- 0.01 metre (1 metre is equal to 100 centimetres)
- about 0.393700787401575 inch (1 inch is equal to 2.54 centimetres)
^{[1]}

1 cubic centimetre is equal to 1 millilitre, under the SI system of units.

## Uses of centimetre

The centimetre is also used:

- sometimes, to measure how much rain has fallen into a rain gauge;
^{[2]} - for heights of people, especially athletes, in metric nations;
- in maps, centimetres are used to change from map scale to real-world scale of landscapes (kilometres).

## Unicode symbols

The centimetre has Unicode symbols so it can be written in Mandarin Chinese, Japanese and Korean characters. ^{[3]}

- centimetre (㎝) - code 339D
- square centimetre (㎠) - code 33A0
- cubic centimetre (㎤) - code 33A4

They are placed into one character, and it is mostly used with East Asian fonts.

## References

- ↑ Inch - from Eric Weisstein's World of Physics
- ↑ "Rain Measurement, Rain Gauge, Wireless Rain Gauge, Rain Gage, Rain Gauge Data". Weathershack.com.
- ↑ [1] CJK Compatibility excerpt from The Unicode Standard, Version 4.1.

- CJK Compatibility excerpt from The Unicode Standard, Version 4.4 and co-exterior users.