Molar Mass Calculator
Type a chemical formula. You get its molar mass, element by element, from the standard atomic weights.
Example — Molar mass of H2O18.015 g/mol
How we got it — the example, step by step
- H: 2 × 1.008 = 2.016 g/mol.
- O: 1 × 15.999 = 15.999 g/mol.
- Add them up: 2.016 + 15.999 = 18.015 g/mol.
Check it backwards
The breakdown is the check: the parts add to the total, and each part is count × the standard atomic weight printed in the steps.
Questions people also ask
Which atomic weights does it use?
The standard (CIAAW) conventional atomic weights — H 1.008, C 12.011, O 15.999, and so on — the same values printed in textbooks. About 50 common elements are in the table; a formula using an element outside it gets a plain 'not in the table yet', not a guess.
Can it handle brackets?
Yes — Ca(OH)2 is read as one calcium, two oxygens and two hydrogens, and nested groups work the same way.