Molar Mass Calculator

Compute molar mass from a chemical formula. Supports common elements; multi-character symbols and subscripts.

Inputs

Examples: H2O, NaCl, CaCO3, C6H12O6.

Result

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How to use this calculator

  • Type the formula (case-sensitive: O ≠ o).
  • Read molar mass.

About this calculator

Molar mass is the mass of one mole of a substance, in g/mol. For a molecule, sum the atomic masses of all atoms. H2O = 2 × 1.008 + 15.999 = 18.015. The calculator handles common formulas with single-letter and two-letter element symbols and integer subscripts. Parentheses and water-of-hydration aren't parsed; expand them yourself if needed.

Frequently asked

Why case-sensitive?+
Because Co (cobalt) ≠ CO (carbon monoxide). Element symbols start with a capital letter; the optional second letter is lowercase.
Does this handle parentheses like Ca(OH)₂?+
No — expand to CaO2H2 yourself. The parser is intentionally simple to keep the math transparent.
Why are atomic masses not whole numbers?+
Because they're weighted averages over natural isotope abundances. Carbon is 12.011 (mostly ¹²C with some ¹³C).
Where do these atomic masses come from?+
IUPAC 2021 standard atomic weights, rounded to 3-5 decimals.
Most common formulas to check?+
H2O = 18.015, CO2 = 44.01, NaCl = 58.44, C6H12O6 = 180.16, C8H10N4O2 (caffeine) = 194.19.

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