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Molecular Weight Calculator

Calculate the molar mass of a compound from its atomic composition, then find moles from a weighed sample. Perfect for stoichiometry problems and lab preparation of solutions.

Carbon Atoms (C) (atoms)

Hydrogen Atoms (H) (atoms)

Oxygen Atoms (O) (atoms)

Nitrogen Atoms (N) (atoms)

Sample Mass (g)

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Chemistry

Molecular Weight Calculator

Compute the molecular weight (molar mass, g/mol) of a CHON-containing molecule from the number of carbon, hydrogen, oxygen, and nitrogen atoms in its formula, with an optional isotope-correction factor. Useful for routine stoichiometry on organic and biological molecules where C, H, O, and N dominate the elemental composition.

Carbon Atoms (C) (atoms)

Hydrogen Atoms (H) (atoms)

Oxygen Atoms (O) (atoms)

Nitrogen Atoms (N) (atoms)

Isotope Correction

Fill in the required fields to see your result.

Key differences

	Molecular Weight Calculator	Molecular Weight Calculator
Category	Chemistry	Chemistry
Inputs required	5	5
Result	Number of Moles (mol)	Molecular Weight (g/mol)
What it does	Calculate the molar mass of a compound from its atomic composition, then find moles from a weighed sample. Perfect for stoichiometry problems and lab preparation of solutions.	Compute the molecular weight (molar mass, g/mol) of a CHON-containing molecule from the number of carbon, hydrogen, oxygen, and nitrogen atoms in its formula, with an optional isotope-correction factor. Useful for routine stoichiometry on organic and biological molecules where C, H, O, and N dominate the elemental composition.