Science

Molecular Weight Calculator

Calculate the molar mass of any chemical formula using standard atomic weights.

Use standard capitalization (e.g., NaCl, not nAcl or NACL). Supports brackets like Ca(OH)2.
Molar Mass
—
g/mol
Elemental Composition
How to Use
  1. Type a standard Chemical Formula into the input box.
  2. Ensure proper capitalization (e.g., Co is Cobalt, CO is Carbon Monoxide).
  3. Use numbers for quantities (e.g., H2O).
  4. Use parentheses for nested groups (e.g., Ca(OH)2).
  5. The calculator instantly breaks down the mass contribution of each element and computes the total molar mass.

Formula

Molar Mass Math:
Molar Mass = Σ (Atomic Weight of Element × Number of Atoms)

Example for H₂O:
H: 1.008 × 2 = 2.016 g/mol
O: 15.999 × 1 = 15.999 g/mol
Total = 18.015 g/mol

The Molecular Weight Calculator determines the precise molar mass of chemical compounds. Using standard atomic weights from the periodic table, it parses complex formulas with parentheses to provide mass fractions and total molecular weight in grams per mole (g/mol).