Molecular Weight Calculator
Calculate molar mass and elemental composition from any chemical formula
Chemical Formula
Quick examples:
Formula Tips
• Element symbols: first letter uppercase (H, He, Ca, Fe)
• Numbers follow elements: H2O, not H₂O
• Parentheses supported: Ca(OH)2, Al2(SO4)3
• Case-sensitive: Na ≠ na
• Numbers follow elements: H2O, not H₂O
• Parentheses supported: Ca(OH)2, Al2(SO4)3
• Case-sensitive: Na ≠ na
Molecular Weight
Molar Mass
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Total Atoms
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Unique Elements
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Formula Breakdown
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About Molecular Weight
Molecular weight (molar mass) is the sum of atomic weights of all atoms in a formula, in grams per mole (g/mol). One mole of any substance contains 6.022 × 10²³ particles (Avogadro's number). Molar mass is essential for stoichiometry calculations — converting between grams and moles.
Common molar masses: H₂O = 18.015, NaCl = 58.44, CO₂ = 44.01, glucose (C₆H₁₂O₆) = 180.16, ethanol (C₂H₅OH) = 46.07 g/mol. Atomic weights used are 2021 IUPAC standard values.
lightbulb Example
Glucose: C₆H₁₂O₆
1C: 6 × 12.011 = 72.066
2H: 12 × 1.008 = 12.096; O: 6 × 15.999 = 95.994
✓ MW = 180.156 g/mol