Mass Percent Calculator
Works out the percentage by mass of a solution.
Mass percent
— %
Share sends a link that reopens these numbers. Copy details pastes the full breakdown as a list.
Total mass of solution —
Mass fraction —
The formula
mass % = mass of solute ÷ (mass of solute + mass of solvent) × 100
The denominator is the whole solution, solute included.
What to watch out for
For the percentage of an element in a compound, the molar mass calculator lists each element’s mass percent.
Frequently Asked Questions
What is the mass percent of 25 g of salt in 225 g of water?
10.0%. The total is 250 g, not 225 g.
What is the mass percent of oxygen in water?
88.8%: the oxygen’s atomic weight over water’s molar mass.