Chemistry

Atomic Mass Calculator

Lets users compute and verify atomic mass instantly with formula, steps and examples — no manual math.

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Average atomic mass
35.4529 u

Average atomic mass = Σ(mass × abundance) = 35.453 u.

About this calculator

Average atomic mass = Σ (isotope mass × fractional abundance). Chlorine's two isotopes (35 at 75.77%, 37 at 24.23%) give the familiar 35.45 u.

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