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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

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Chemistry

Percent Composition Calculator

Find the mass percentage of any element in a compound. Essential for chemistry students and lab work when verifying empirical formulas or analyzing compound purity.

Mass of element (g)

Total molecular mass (g)

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Key differences

	Molecular Weight Calculator	Percent Composition Calculator
Category	Chemistry	Chemistry
Inputs required	5	2
Result	Molecular Weight (g/mol)	Percent Composition (%)
What it does	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.	Find the mass percentage of any element in a compound. Essential for chemistry students and lab work when verifying empirical formulas or analyzing compound purity.