Molar mass calculator
Type a chemical formula to get its molar mass and percent composition instantly.
Molar mass
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g/mol
| Element | Atoms | Atomic mass | Total (g/mol) | Mass % |
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About the calculator
What is molar mass?
Molar mass is the mass of one mole (6.022 × 10²³ particles) of a substance, in grams per mole (g/mol). It equals the sum of the atomic masses of all atoms in the formula.
How do I calculate molar mass by hand?
Count each element’s atoms in the formula, multiply each count by that element’s atomic mass, and add the results. For water (H2O): 2 × 1.008 + 15.999 = 18.015 g/mol.
How do I enter hydrates and brackets?
Use parentheses or square brackets for groups, like Ca(OH)2 or K4[Fe(CN)6]. For hydrates, separate the parts with a dot, asterisk or middle dot, like CuSO4·5H2O or CuSO4*5H2O.
Are element symbols case-sensitive?
Yes. Co is cobalt but CO is carbon monoxide. Write the first letter of every symbol as a capital and the second letter in lower case.