**kilogram per square metre**

##### SI coherent derived unit

Name | Symbol | Derived quantity | ||

kilogram per square metre |
kg m^{−2} |
surface density | ||

## DefinitionThe kilogram per square metre, symbol kg m An area of one square metre with a mass of one kilogram has a surface density of one kilogram per square metre. |

### Paper

The surface density of paper is measured in units of grams per square metre, symbol g/m^{2}.

### Body mass index

Body mass index (BMI) is defined as body mass divided by the square of body height. BMI is expressed in units of kg/m^{2}, although in common use the units are generally omitted.