Molar Mass Calculator Tool

Determine the Molar mass and Percent mass composition of a linear chemical formula

Enter a valid molecular formula and press the calculate button to determine the correct molar mass. Atomic mass values for individual elements can be obtained from the Periodic Table of the Elements. Results are expressed in terms of grams/mol.

Guidelines and examples for entering valid Molecular Formulas
  • Formulas must start with an element or grouped set of elements. This can be followed by an integer, group of additional elements contained within matching parenthesis or square brackets, a molecule of crystallization marker or a combination of all three of these things.
  • Formulas can contain spaces.
  • Formulas cannot begin with numbers or a molecule of crystallization markers (a period '.' or middle dot '·').
  • Formulas cannot contain hyphens.
  • Molecule(s) of crystallization must be placed at the end of the formula and denoted by a period '.' or middle dot '·'

Examples of valid Molecular Formulas and the equivalent Hill Notation

CH3CH2COOHC3 H6 O2
C5 H6 Cr12 O2C5 H6 Cr12 O2
KFe(Fe(CN)6)30C180 Fe31 K N180
Na2B4O7(H2O)5H10 B4 Na2 O12
(CH3CH2COOH)(C14H12(Na)5)C17 H18 Na5 O2
((CH3CH2COOH)2(C14H12(Na)5))4H4O4P2Na25C80 H100 Na45 O20 P2
CH3CH2Br.2H2O2PC2 H9 Br O4 P2
C22 Cu SO4·5 H2OC22 H10 Cu O9 S

Molecular Formula

Please note that the molar mass calculator does not currently calculate isotopes. We are working towards a resolution. Please contact a technical support scientist if you need further assistance.