Molar Mass Calculator
Calculate the molar mass (molecular weight) of any chemical compound by entering its molecular formula.
Use standard element symbols. Parentheses supported. Case-sensitive (e.g. Co not CO).
Enter a formula above and click Calculate.
Formula
Molar Mass (M) = Σ (ni × Ai)
Where ni is the number of atoms of element i in the formula unit, and Ai is the standard atomic weight of element i in g/mol. The result is expressed in grams per mole (g/mol), also written as Da (daltons) or u (unified atomic mass units) for a single molecule.
Elements are listed using the Hill system: carbon first, hydrogen second, then all remaining elements alphabetically.
Assumptions & References
- Atomic weights are standard atomic weights from IUPAC 2021 recommendations (conventional values for naturally occurring isotopic compositions).
- The formula parser supports nested parentheses
()and square brackets[]with multipliers (e.g.Ca(OH)2,Al2(SO4)3,Fe[Co(CN)6]). - Element symbols are case-sensitive:
Co= cobalt,CO= carbon + oxygen. - Isotopically labelled compounds and charged species (ions) are not supported; the calculator uses natural isotopic abundances only.
- Atomic weights for radioactive elements with no stable isotopes (e.g. Tc, Po) are given as the mass number of the most stable or most common isotope.
- Reference: IUPAC Commission on Isotopic Abundances and Atomic Weights — Pure Appl. Chem. 2021, 93(12), 1515–1544.