Chemical Equation Balancer

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Balanced Equation

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Enter an equation

Type a chemical equation above to balance it automatically.

History
⇋ Redox half-reaction combiner (beta)

Enter balanced half-reactions with electrons (e-). The tool equalizes electrons and combines into a net reaction.

📚 Reaction database
TypeUnbalancedBalanced

1 What is a Chemical Equation?

A chemical equation is a symbolic representation of a chemical reaction. Reactants appear on the left side and products on the right, separated by an arrow (→). Each substance is written as a chemical formula (e.g., H₂O for water). The law of conservation of mass requires that every atom present in the reactants must also appear in the products — nothing is created or destroyed, only rearranged.

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Key insight: Balancing an equation means finding the smallest set of integer coefficients that make atom counts equal on both sides. This tool uses Gaussian elimination on the atom matrix for a mathematically rigorous solution.

2 How to Balance Chemical Equations

Follow these four steps for any equation. This is the exact process our balancer automates:

1

Write Formulas

Write correct chemical formulas for all reactants and products. Do not change subscripts.

2

Count Atoms

Count atoms of each element on both sides. Include atoms inside parentheses.

3

Add Coefficients

Place whole-number coefficients before formulas to equalize counts. Start with metals.

4

Verify & Simplify

Double-check every element. Reduce coefficients to the smallest whole-number ratio.

3 Common Reaction Types

Combustion

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

Acid-Base

HCl + NaOH → NaCl + H₂O

Synthesis

2H₂ + O₂ → 2H₂O

Decomposition

2KClO₃ → 2KCl + 3O₂

Single Replacement

Zn + 2HCl → ZnCl₂ + H₂

Double Replacement

AgNO₃ + NaCl → AgCl + NaNO₃

4 Redox Reactions Primer

Redox (reduction–oxidation) reactions involve electron transfer. The substance that loses electrons is oxidized; the one that gains electrons is reduced. Use the half-reaction method to balance:

  1. Split into oxidation and reduction half-reactions
  2. Balance atoms other than O and H
  3. Balance O with H₂O and H with H⁺ (acidic) or OH⁻ (basic)
  4. Balance charge with electrons (e⁻)
  5. Equalize electrons between half-reactions and combine
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Tip: Use the Redox tab in our tool to enter your balanced half-reactions directly. It will equalize electrons and produce the net ionic equation automatically.