Molecular Weight Calculator
Calculate the molecular weight (molar mass) of any chemical compound from its formula. Handles parentheses, multi-character elements, and subscripts.
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About the Molecular Weight Calculator
Molecular weight (molar mass) is the sum of the atomic weights of all atoms in a molecule, expressed in grams per mole (g/mol). It is a fundamental value in chemistry used for stoichiometry, solution preparation, and reaction balancing. For example, water (H₂O) has a molecular weight of 18.015 g/mol. Once you know the molecular weight, use our Molarity Calculator to calculate solution concentrations from mass.
This calculator supports multi-character elements (Na, Ca, Cl, etc.), subscript numbers, and nested parentheses for complex molecules like Ca(OH)₂ or Al₂(SO₄)₃. The elemental composition table shows each element's count, contribution to total mass, and mass percentage. For physical properties like density of compounds, visit our Density Calculator.
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For a related calculation, use Wind Chill Calculator to calculate wind chill temperature using the NWS formula. Shows frostbite risk thresholds. Alternatively, use Molarity Calculator to calculate molarity, moles, or volume for solutions. Outputs mol/L, mmol/L, and μmol/L.