Percent Composition Calculator

Calculate percent composition of chemical compounds using % = (mass part / mass total) × 100. Calculate from chemical formula (H₂O, CO₂, C₆H₁₂O₆, etc.), from experimental masses, find element mass from total mass and percent, or calculate total mass from element mass and percent. Features atomic masses for 50+ elements and 15 common compound formulas. Perfect for chemistry students.