Calculate oxidation number

Assign common oxidation numbers by formula parsing and charge balance.

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ToolOxidation Number Calculator
Input
Output
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How it works

Atoms are counted, common fixed oxidation states are assigned, and charge balance solves one remaining state. The result shows assumptions and solved contributions for each element.

  • The fixed-state table covers common classroom rules.
  • This is a rule-based estimate rather than a complete chemical database.

Worked example

Potassium permanganate
Manganese is the only element without a fixed rule, so it is solved by charge balance
Input
											KMnO4
Output
												Formula: KMnO4
Breakdown: K: +1, Mn: +7, O: -2
Solved element: Mn

When to use this

Redox lessons assign sulfate states, balancing exercises identify oxidation, and worksheets check charge neutrality.

Edge cases

  • Peroxides and hydrides use exceptions.
  • Multiple unresolved elements are underdetermined by charge alone.
  • Mixed-valence compounds can have an average state rather than one state per atom.