Molar mass calculator

How it works

Type a chemical formula such as H2O or Ca(OH)2.

The formula

Molar mass = Σ(number of atoms × atomic mass of the element), in g/mol.

Worked example

H₂O = 2 × 1.008 + 15.999 = 18.015 g/mol.

Good to know

• Atomic masses are standard IUPAC values; isotopes can shift them slightly.