Chemical Equation Balancer

What this generator does

Parses each formula into element counts, searches for the smallest whole-number coefficients that make every element balance, reduces them to lowest terms, and then recounts every atom on each side from the formulas.

How to use this tool

1. Choose a reaction from the list.
2. Read the balanced equation with its coefficients.
3. Check the table: the two columns match for every element.
4. Try methane combustion, which is the classic first example.

Understanding the controls

Reaction

A list of common reactions from school chemistry — combustion, synthesis, decomposition and displacement. Each parses its own formulas rather than carrying a stored answer.

Common use cases

• Checking a balancing answer against a worked one
• Teaching conservation of mass with the counts shown
• Producing balanced equations for a chemistry worksheet
• Seeing why coefficients must be in lowest terms
• Understanding why a coefficient multiplies every atom in a formula

How this generator works

Each formula is parsed into a count of atoms per element, including bracketed groups like the hydroxide in calcium hydroxide. A bounded search then tries small whole-number coefficients until every element balances — reactions at this scale never need large ones. The coefficients are divided by their greatest common divisor so the answer is in lowest terms. Before display every element is recounted from the formulas with the coefficients applied, and the two sides must match exactly.

Randomness and fairness

Nothing here is random. A reaction has one balanced form in lowest terms.

For how randomness is produced across the whole site, see how Generate Random works.

Limitations and good to know

• The search uses coefficients up to twelve, which covers school-level equations but not every industrial reaction.
• States of matter, reaction conditions and reversibility are not shown — this is the stoichiometry only.
• Redox half-equations, which need charge balanced as well as atoms, are outside what this does.
• The element list covers common ones rather than the whole periodic table.

Privacy and your data

The balancing runs in your browser and your choice of reaction is not transmitted, stored or included in analytics.