Formal Charge Calculator
🔥 Thermochemistry & Bonding. Use the Formal charge formula to find formal charge, valence electrons v, non-bonding electrons n, bonding electrons b: pick the value you want, type the others, and the answer updates as you go.
V = valence electrons, N = non-bonding (lone-pair) electrons, B = bonding electrons. Select an atom in the Molecule Builder to use it.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Formal charge | no unit |
| Valence electrons V | no unit |
| Non-bonding electrons N | no unit |
| Bonding electrons B | no unit |
Worked example
Find the formal charge when Valence electrons V = 6, Non-bonding electrons N = 4, Bonding electrons B = 4.
Using FC = V - N - B/2: Formal charge = 5.839 × 10⁻¹⁰.
Frequently asked questions
What is the formula for Formal charge?
FC = V - N - B/2. V = valence electrons, N = non-bonding (lone-pair) electrons, B = bonding electrons. Select an atom in the Molecule Builder to use it.
What do the letters stand for, and what units are used?
Formal charge, Valence electrons V, Non-bonding electrons N, Bonding electrons B.
How do you calculate formal charge?
Put the values into FC = V - N - B/2. For example, with Valence electrons V = 6, Non-bonding electrons N = 4, Bonding electrons B = 4, formal charge = 5.839 × 10⁻¹⁰.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (formal charge, valence electrons v, non-bonding electrons n, bonding electrons b) and fill in the others: it rearranges the formula for you.
