Molecular Weight Calculator
Calculate the molecular weight (molar mass) of chemical compounds from their formula. Shows element-by-element breakdown with atomic weights.
Inputs
Results
Molecular Weight
18.015 g/mol
How to Use This Calculator
- Select a compound from the list (water, NaCl, glucose, CO2, etc.) or enter a custom formula.
- Review the element-by-element breakdown showing atomic weight and count for each element.
- Check total molecular weight in g/mol.
- Use molecular weight to convert between grams and moles in stoichiometry calculations.
- Remember: molecular weight in g/mol equals the mass of one mole of that substance.
What each input means
- Select Compound
- Choose a common compound or molecule.
How this is calculated
Formula
Molecular Weight = Sum of (atomic weight × count) for each element. Atomic weights from IUPAC 2021 standard values.Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.
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