# Mass fraction

## Description

In a mixture, the mass fraction is the amount of mass of one substance, divided by the mass of the total mixture. The sum of all the mass fractions is equal to 1. Mass fraction can also be expressed, with a denominator of 100, as percentage by mass.

Related formulas## Variables

w_{i} | Mass fraction (dimensionless) |

m_{i} | Mass of one substance (kg) |

m_{total} | Total mass (kg) |