Molecular Weight Calculator

M = Σ (nᵢ × Aᵢ)

Calculate the molecular or formula mass of a chemical formula, with a per-element breakdown.

Inputs

Chemical formula

Use · for hydrates. Parentheses and brackets are supported.

Result

249.677 g/mol

Formula mass of CuSO4·5H2O

Calculation

Formula
M = Σ (nᵢ × Aᵢ)
Substitution
9 × 15.999 + 1 × 63.546 + 1 × 32.06 + 10 × 1.008
Total
M = 249.677 g/mol

Inputs

Formula: CuSO4·5H2O

IUPAC conventional atomic weights (abridged), values in g/mol.

Element breakdown

Element	Atoms	Atomic weight	Contribution	Share
O	9	15.999	143.991	57.7%
Cu	1	63.546	63.546	25.5%
S	1	32.06	32.06	12.8%
H	10	1.008	10.08	4.04%

About this calculator

The formula mass is the sum of the atomic weights of every atom in the formula unit. The parser supports element symbols, numerical subscripts, parentheses and brackets (including nested groups), leading coefficients and hydrate notation with the middle dot (·), for example CuSO4·5H2O.

Invalid formulas are rejected rather than guessed. Atomic weights come from a separate, reviewable data file: IUPAC conventional atomic weights (abridged), values in g/mol.

LabCalc is provided as a calculation aid. Users remain responsible for verifying calculations, units, chemical compatibility, experimental procedures and applicable safety requirements before laboratory use.

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