About the Mass Percent Calculator
Mass percent (w/w) of a solution from solute and solvent masses, in %, ppm and ppb.
Also known as: weight percent, w/w percentage, percent by mass solution, mass fraction.
How to use this calculator
- Enter solve for and the other fields.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Review the breakdown shown under the main result.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
% w/w = mass of solute ÷ total mass of solution × 100
Worked example
Using the values pre-filled in the calculator above:
- Solve for: Mass percent
- Mass of solute = 25 g
- Mass of solvent = 175 g
the calculator returns:
- Mass percent: 12.5%
- Total solution mass: 200 g
- Parts per million: 125,000
- Mass fraction: 0.125