Molar Mass Calculator
Compute the molar mass and percent composition of any chemical formula, including parentheses and hydrates like CuSO4·5H2O.
Last reviewed by the Radiatus Cloud team
Supports parentheses, e.g. Al2(SO4)3, and hydrates written with a dot, e.g. CuSO4.5H2O. Atomic weights from IUPAC 2021.
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Compute molar mass from a formula
The molar mass of a compound is the mass of one mole of it, needed for any quantitative chemistry. This calculator computes the molar mass and percent composition of any chemical formula, including parentheses, from the atomic masses of its elements.
How the formula becomes a mass
A chemical formula is a recipe of atoms, and its molar mass is the sum of the atomic masses of all those atoms, with each element counted by how many times it appears. Parentheses and subscripts multiply groups, which is exactly where hand calculation goes wrong. The percent composition then shows what fraction of the total mass each element contributes, which is useful for understanding a compound and for laboratory calculations. The calculator parses the formula correctly, including nested groups.
Accurate chemistry, fast
Everything runs in your browser, so nothing you enter is uploaded and the tool works without an account. That keeps your study material and notes private on your own machine while you learn.
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Frequently Asked Questions
What does it calculate?
The molar mass of a chemical formula, the sum of the atomic masses of all its atoms, plus the percent composition of each element.
Does it handle parentheses?
Yes. It parses parentheses and subscripts correctly, multiplying grouped atoms, which is exactly where hand calculation tends to go wrong.
What is percent composition?
The fraction of a compound’s total mass contributed by each element, useful for understanding the compound and for laboratory calculations.
Why is molar mass important?
Because it is needed for any quantitative chemistry, converting between mass and moles in reactions and solutions.
Is my input uploaded?
No. The calculation runs entirely in your browser.
Privacy & Security
Runs entirely in your browser. No data is sent to any server.
How to Use
Type a chemical formula such as C6H12O6 or Al2(SO4)3. The molar mass and each element's contribution appear instantly.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.