The molar mass of a compound is the weight of one mole of that substance in grams — a value chemists use constantly for converting between mass and number of molecules. Enter a chemical formula (e.g., H2O, NaCl, C6H12O6) or select a common compound from the dropdown to get the molar mass in g/mol, along with the total number of atoms in the formula.
Molar Mass
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Chemical Formula
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Total Number of Atoms
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Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). It's calculated by adding up the atomic masses of all atoms in a chemical formula, multiplied by their respective quantities.
Use proper capitalization for elements (H, O, Na, Cl) and include numbers for quantities. Examples: H2O for water, NaCl for salt, Ca(OH)2 for calcium hydroxide. Parentheses indicate groups that are repeated.
The terms are often used interchangeably. Molecular weight is the mass of a single molecule, while molar mass is the mass of one mole (6.022 × 10²³ molecules) of a substance. Both are expressed in g/mol.
Yes, the calculator works for both molecular compounds (like H2O) and ionic compounds (like NaCl). The calculation method is the same - sum the atomic masses of all atoms present.
Molar mass is essential for stoichiometry calculations, determining how much of each reactant is needed in chemical reactions, converting between grams and moles, and calculating concentrations of solutions.
The calculator uses standard atomic weights published by IUPAC (International Union of Pure and Applied Chemistry), which are the internationally accepted values for atomic masses.
Yes, include the water molecules in your formula. For example, copper sulfate pentahydrate would be entered as CuSO4·5H2O or CuSO4*5H2O, and the calculator will include the mass of the water molecules.