Mass Percent Calculator Formula

Understand the math behind the mass percent calculator. Each variable explained with a worked example.

Formulas Used

Mass Percent

mass_percent = (mass_solute / mass_solution) * 100

Mass of Solvent

mass_solvent = mass_solution - mass_solute

Variables

VariableDescriptionDefault
mass_soluteMass of Solute(g)10
mass_solutionMass of Solution(g)100

How It Works

How to Calculate Mass Percent

Formula

Mass % = (mass of solute / mass of solution) × 100

Mass percent tells you the grams of solute per 100 grams of solution.

Worked Example

10 g of salt dissolved in 90 g of water (100 g solution).

mass_solute = 10mass_solution = 100
  1. 01Mass % = (10 / 100) × 100
  2. 02Mass % = 10%

Frequently Asked Questions

What is mass percent?

Mass percent (w/w%) is the ratio of solute mass to total solution mass, multiplied by 100.

How is it different from volume percent?

Mass percent uses masses; volume percent uses volumes. Mass percent is temperature-independent.

Is mass percent the same as purity?

Often yes. Purity of a substance is commonly expressed as mass percent of the desired component.

Ready to run the numbers?

Open Mass Percent Calculator