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Calculate molecular weight instantly with element-by-element breakdown. Perfect for stoichiometry, lab work, and chemistry homework.
Click any compound below to instantly calculate its molar mass
Type your chemical formula using standard notation (e.g., H2O, NaCl)
We identify each element and its count in the formula
NIST atomic masses are used for precise calculations
Total molar mass is calculated with element breakdown
Tips for entering chemical formulas correctly
Use capital letters for element symbols. Two-letter symbols use lowercase for the second letter.
Ca, Na, Fe, Cl, MgWrite subscripts as regular numbers after the element symbol.
H2O, CO2, C6H12O6Write all elements in sequence with their subscripts.
NaCl, H2SO4, Ca(OH)2Get molar mass calculations in milliseconds with real-time updates
Uses official NIST atomic weight values for maximum accuracy
See contribution of each element with percentage breakdown
Perfect for learning chemistry and understanding molecular composition
Works directly in your browser, no downloads or sign-ups required
Precise enough for professional laboratory calculations
Molar mass is the mass of one mole of a substance, expressed in grams per mole (g/mol). It equals the sum of the atomic masses of all atoms in the molecular formula.
Multiply the atomic mass of each element by its subscript (number of atoms), then add all the values together. For H2O: (2 × 1.008) + (1 × 15.999) = 18.015 g/mol
Molar mass (g/mol) and molecular weight (amu or Da) have the same numerical value but different units. Molar mass is mass per mole, while molecular weight is mass per molecule.
Molar mass is essential for stoichiometry calculations, converting between mass and moles, preparing solutions of specific concentrations, and understanding reaction quantities.
Our calculator uses NIST (National Institute of Standards and Technology) atomic masses, which are the most accurate and up-to-date values available for chemical calculations.
VerChem offers a complete suite of chemistry calculators and tools