The Percent Composition Calculator helps you quickly determine the percentage by mass of each element in a compound. By entering the mass of individual elements, this tool calculates how much each element contributes to the overall composition of the compound. It is especially useful for students, teachers, and professionals in chemistry who want to analyze compounds, check formulas, or verify experimental results. With this calculator, you can easily find the percent composition of elements in compounds like water (H₂O), carbon dioxide (CO₂), and many others.