Molar Mass Calculator — Chemical Formula to Molecular Weight
Calculate the molar mass of any chemical compound from its formula (H2O, NaCl, C6H12O6). Shows elemental breakdown, mass percent composition, and Avogadro's number conversions.
Common:
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Molar Mass (g/mol)
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Parsed Formula
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Total Atoms
Elemental Composition
Frequently Asked Questions
What is molar mass?
Molar mass is the mass of one mole (6.022×10²³ particles) of a substance, expressed in grams per mole (g/mol). It equals the sum of atomic masses of all atoms in the molecular formula. For example, H₂O: 2(1.008) + 15.999 = 18.015 g/mol.
How do I write a chemical formula for this calculator?
Use standard chemical notation with capital letters for element symbols. Numbers follow the element: H2O, NaCl, C6H12O6, Ca(OH)2, H2SO4. Parentheses with subscripts are supported: Ca(OH)2 = Ca + 2O + 2H.
What is the difference between molar mass and molecular weight?
Molar mass (g/mol) is numerically equal to molecular weight (in unified atomic mass units, u or Da) but uses different units. The terms are often used interchangeably in chemistry contexts.
What is elemental composition?
Elemental composition (mass percent) shows what fraction of the total mass each element contributes: % element = (atoms × atomic mass / molar mass) × 100. For H₂O: O = 15.999/18.015 × 100 = 88.8%, H = 2(1.008)/18.015 × 100 = 11.2%.
How many atoms are in one mole?
1 mole = 6.02214076 × 10²³ particles (Avogadro's number). So 1 mole of H₂O contains 6.022×10²³ water molecules, or 2 × 6.022×10²³ hydrogen atoms and 6.022×10²³ oxygen atoms.