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Molecular Weight Calculator

Enter a chemical formula to calculate its molecular weight with a full element breakdown

Examples: H2O, C6H12O6, NaCl, Ca(OH)2, CuSO4·5H2O, Fe2(SO4)3
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Molecular Weight (g/mol)

About the Molecular Weight Calculator

This molecular weight calculator computes the molar mass of a chemical compound based on its formula. It parses the formula to count atoms of each element and multiplies by the standard atomic weights to determine the total molecular weight in grams per mole.

How It Works

Molecular Weight = Σ (Element Atomic Weight × Number of Atoms)

Frequently Asked Questions

How do I enter hydrated compounds?

Use the middle dot (·) followed by the water formula. For example, CuSO4·5H2O is entered as "CuSO4·5H2O" (using the period key or the middle dot character). The calculator will correctly parse the water of hydration.

What is molecular weight used for?

Molecular weight (molar mass) is essential for converting between mass and moles in chemical reactions, preparing solutions of specific concentrations, stoichiometric calculations, and determining empirical and molecular formulas of compounds.