Molar Mass and Mass Percent Composition Calculator

Interactive Molar Mass and Mass Percent Composition Calculator

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 our Periodic Table of the Elements . Results are expressed in terms of grams/mol.

Guidelines for entering valid Molecular Formulas · Examples of valid Molecular Formulas.
Molecular Formula:
Guidelines 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
Valid Linear Molecular Formula Formula converted to Hill Notation
1. CH3CH2COOH C3 H6 O2
2. C5 H6 Cr12 O2 C5 H6 Cr12 O2
3. KFe(Fe(CN)6)30 C180 Fe31 K N180
4. Na2B4O7(H2O)5 H10 B4 Na2 O12
5. (CH3CH2COOH)(C14H12(Na)5) C17 H18 Na5 O2
6. ((CH3CH2COOH)2(C14H12(Na)5))4H4O4P2Na25 C80 H100 Na45 O20 P2
7. CH3CH2Br.2H2O2P C2 H9 Br O4 P2
8. C22 Cu SO4 ·5 H2O C22 H10 Cu O9 S

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