Molar Mass & Moles Calculator Online
Compute molar mass from a chemical formula and convert between mass, moles and number of molecules. Supports parentheses and hydrates like CuSO4·5H2O.
Filled automatically from the formula; you can override it
I know the
Mass, g
18
Amount of substance, mol
0.99916736
Molecules
6.0171e+23
Frequently asked questions
How is molar mass calculated from a formula?
The formula is parsed element by element — including parentheses and hydrate parts like CuSO4·5H2O — and multiplied by the standard atomic masses from the periodic table.
How many molecules are in one mole?
Exactly the Avogadro constant: 6.02214076×10²³. The calculator multiplies the amount of substance by this number automatically.
Can I enter the molar mass manually?
Yes — the formula field is optional. If you already know the molar mass, just type it into the g/mol field.