Calculate percent composition by mass quickly and accurately. Enter the mass of a component and the total mass to determine what percentage of the sample comes from that component.
Choose what you want to calculate and enter the known values.
Percent composition tells you what percentage of the total mass of a compound, mixture, or sample is contributed by a particular component. It is commonly expressed as a percentage by mass.
For example, if a 100 gram sample contains 25 grams of a particular component, that component represents 25% of the sample by mass.
The standard mass percent formula divides the mass of the component by the total mass and multiplies the result by 100.
Choose whether you want to find percent composition, component mass, or total mass.
Enter the available mass and percentage values into the calculator fields.
Click Calculate to instantly see the result and the mathematical formula used.
Suppose a sample has a total mass of 80 grams and one of its components has a mass of 20 grams. The percent composition is:
| Find | Formula | Output |
|---|---|---|
| Percent Composition | (Component Mass ÷ Total Mass) × 100 | % |
| Component Mass | (Percentage ÷ 100) × Total Mass | Mass |
| Total Mass | Component Mass ÷ (Percentage ÷ 100) | Mass |
Determine how much each element contributes to the overall mass of a compound.
Compare the relative mass contribution of different components in a mixture.
Use mass percentages when analyzing samples and reporting laboratory composition data.