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Molar Mass Calculator

Get formula weight from a chemical formula, plus moles and particles if you type a mass.

 

Molar mass (g/mol)
Moles
Particles

About this calculator

Use this calculator when weighing a reagent: type H2O or Ca(OH)2 and, optionally, a mass to get g/mol, moles, and a particle count.

The calculation is moles = mass / M and particles = moles × N_A, with N_A = 6.02214076×10²³. Nested parentheses work. Hydrates such as CuSO4·5H2O are accepted. Atomic weights are conventional IUPAC values, not a specific isotope. Leave mass empty if you only want M.

Mass can be entered in grams (g), ounces (oz), or pounds (lb); the calculator converts to grams before dividing by M.

Formula: Formula such as H2O, C6H12O6, Ca(OH)2, Fe2(SO4)3, or CuSO4·5H2O.

Mass, optional: Sample mass if you also want moles. Leave blank for molar mass only.

Molar mass (g/mol): Formula weight in g/mol.

Moles: Amount of substance if a mass was entered.

Particles: Number of formula units, moles × N_A.