Mass Percent Calculator

Enter Chemical Formula (e.g., H2O, C6H12O6, NaCl):

Enter the chemical formula using standard notation. Subscripts are automatically detected.

Percent Composition Results

Element	Atoms	Atomic Mass	Total Mass	Percent

What is Percent Composition?

Percent composition, also known as mass percent or weight percent, is the percentage by mass of each element in a compound. It represents the proportion of a particular element’s mass relative to the total mass of the compound.

This concept is fundamental in chemistry for:

Determining empirical formulas from experimental data
Calculating the mass of elements in a given sample of a compound
Understanding the composition of chemical substances
Quality control in chemical manufacturing

Example: Water (H₂O)

Water consists of hydrogen and oxygen. To calculate the percent composition:

Molar mass of H₂O = (2 × 1.008) + 16.00 = 18.016 g/mol

Percent hydrogen = (2.016 / 18.016) × 100% = 11.19%

Percent oxygen = (16.00 / 18.016) × 100% = 88.81%

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Our team of chemistry specialists and educators develops and maintains these precise calculation tools for students, researchers, laboratory professionals, and anyone working with chemical measurements and conversions.

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Chemical Safety Disclaimer

These chemistry conversion tools are for informational, educational, and reference purposes only. They should not replace proper laboratory procedures, safety protocols, or professional chemical analysis. Always follow appropriate safety measures when working with chemicals.

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