Molar Mass Calculator

Calculate molar mass of chemical compounds. Free online molecular weight calculator.

The Molar Mass Calculator computes the molecular weight of any chemical compound from its formula. Enter a chemical formula like H2O or C6H12O6, and get the molar mass in grams per mole. Essential for stoichiometry, solution preparation, and all quantitative chemistry calculations requiring mole-to-gram conversions.

Common use cases

  • Stoichiometry calculations
  • Solution concentration preparation
  • Pharmaceutical formulations
  • Chemical synthesis planning
  • Lab experiment calculations

How to use

  1. Enter the chemical formula (e.g., H2O, NaCl)
  2. Use proper capitalization for elements
  3. Click calculate for molar mass
  4. View element-by-element breakdown
  5. See atomic masses used

FAQ

What is molar mass?

The mass of one mole of a substance in grams/mol. For water (H₂O): 2(1.008) + 15.999 = 18.015 g/mol.

How do I enter formulas?

Use element symbols with proper case (Na, not NA) and numbers for subscripts. H2O, not h2o.

What about parentheses?

Use parentheses for polyatomic ions: Ca(OH)2 means Ca + 2×(O+H).

Where do atomic masses come from?

Standard atomic weights from IUPAC, representing weighted averages of natural isotopes.