Molar Mass Calculator — g/mol from a Chemical Formula

Calculator

A molar mass calculator parses a chemical formula and sums IUPAC standard atomic weight × atom count for every element to give the molar mass in g/mol.

What is it

Molar mass is the mass of one mole (6.022×10²³ particles) of a substance, in g/mol. Reading each element symbol and subscript in the formula and summing standard atomic weight × count gives the total. This tool supports parentheses (Ca(OH)2) and hydrate dot notation (CuSO4·5H2O), and ships the IUPAC/CIAAW 2021 abridged standard atomic weights as static data, so no network request is made.

molar mass (g/mol) = Σ(standard atomic weight × atom count)

How to use

  1. 1Enter a chemical formula (e.g. H2O, CaCO3, Ca(OH)2).
  2. 2Press calculate.
  3. 3Check the molar mass and the per-element breakdown.

Reference

Molar Mass Calculator — g/mol from a Chemical Formula Reference
FormulaMolar mass (g/mol)
H2O18.015
CO244.009
NaCl58.44
CaCO3100.086
C6H12O6180.156
H2SO498.072

Sources & standards

FAQ

What is the molar mass of water (H2O)?

Hydrogen 1.008 × 2 + oxygen 15.999 = about 18.015 g/mol.

Does it handle parentheses in formulas?

Yes. It parses groups like Ca(OH)2 with multipliers and also hydrate dot notation such as CuSO4·5H2O.

Is molar mass calculator input sent to a server?

No. The atomic weight data is built into the tool, so everything is calculated in your browser and no input is sent to a server.

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