basic

Formal Charge Calculator

Formal charge of an atom in a Lewis structure.

Compute the formal charge of an atom in a Lewis structure using FC = V − L − B/2, where V is valence electrons, L is non-bonded (lone-pair) electrons, and B is bonding electrons (2 per bond).

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

FC = V − L − B / 2

In depth

Compute the formal charge of an atom in a Lewis structure using FC = V − L − B/2, where V is valence electrons, L is non-bonded (lone-pair) electrons, and B is bonding electrons (2 per bond).