Molar Mass Calculator
Calculate the molar mass (molecular weight) of any chemical formula — including brackets and hydrates like CuSO4·5H2O — with the mass percentage of each element.
How to use
- 1Type a formula with correct capitalization: H2SO4, Ca(OH)2, CuSO4·5H2O.
- 2See the molar mass, element counts and percent composition.
How it's calculated
Molar mass = Σ (atoms of each element × its standard atomic weight), using IUPAC standard atomic weights.
Frequently asked questions
Why does capitalization matter?
Co is cobalt but CO is carbon monoxide. Each element symbol starts with a capital letter.
How do I enter a hydrate?
Use a dot or asterisk before the water: CuSO4·5H2O or CuSO4*5H2O.
How do I convert grams to moles?
Divide the mass by the molar mass: 98 g of H₂SO₄ (98.08 g/mol) is about 1 mol.