Mass Percent Calculator

Mass Percent Calculator

Mass percent (weight percent, wt%) describes how much of a solution's mass comes from the solute. It is widely used in chemistry labs because it is independent of temperature.

$$\text{mass percent} = \frac{m_{\text{solute}}}{m_{\text{solution}}} \times 100$$

where $m_{\text{solution}} = m_{\text{solute}} + m_{\text{solvent}}$. Given any three of the four values (solute mass, solvent mass, solution mass, mass percent), you can solve for the fourth.

Example: 43 g HCl in 200 g water gives a 243 g solution and a mass percent of $43/243 \times 100 \approx 17.7\%$.

For molarity conversions, see the Concentration Calculator and Molarity Calculator.