How to use the Molar Mass Calculator
- Type the formula, e.g. H2SO4, Ca(OH)2 or CuSO4·5H2O.
- Read the molar mass in g/mol.
- Check the composition table for each element's share.
What does this tool do?
Molar mass is the mass of one mole of a substance — the sum of the atomic masses of every atom in its formula. Water, H₂O, is 2 × 1.008 + 15.999 = 18.015 g/mol.
The parser understands nested brackets, square brackets and hydrates. Symbols are case-sensitive: Co is cobalt, while CO is carbon monoxide.
Why use it?
- Brackets and hydrates supported.
- Percent composition by mass.
- IUPAC standard atomic weights.
The formula
M = Σ (atomic mass × number of atoms)
Privacy
The calculation happens instantly in your browser. The numbers you enter are not sent to our servers or saved. There's no account to create and nothing to install.
Last reviewed by the M2Toolkit team.