b2KIT

Chemical Equation Balancer

Balance chemical equations automatically with step-by-step matrix method. Supports redox half-reactions and combustion.

Tested tool guide Tested browser tools Checked August 16, 2026

What Chemical Equation Balancer does, with a checked example

Enter a skeletal chemical reaction, and the Chemical Equation Balancer finds coefficients that give matching element totals on both sides. It presents the balancing process through a matrix method, including support for combustion equations and redox half-reactions. For a half-reaction, charge and electrons must be considered along with atom counts. The common mistake is changing a formula's subscripts to make totals match. Balancing changes only the coefficients placed before formulas; changing a subscript changes the chemical species itself.

Worked example

A concrete input and expected output from the current implementation.

Input

Fe + O2 -> Fe2O3

Expected output

4 Fe + 3 O2 -> 2 Fe2O3

Two Fe2O3 formula units contain four iron atoms and six oxygen atoms. Four Fe atoms and three O2 molecules supply those same totals, and the coefficient ratio 4:3:2 is already reduced.

How the result is produced

1

Build the conservation matrix

The element symbols define conservation rows, and the entered compounds define coefficient columns. A signed composition matrix records each element's count on the reactant and product sides. Solving the resulting homogeneous system finds coefficient ratios that make every row sum to zero. The displayed steps expose this linear algebra setup without changing any chemical formula.

2

Normalize the coefficients

After a nonzero ratio is found, fractional values can be multiplied by a common denominator and reduced to the lowest whole-number ratio. For Fe + O2 -> Fe2O3, conservation gives one relation for iron and another for oxygen. The normalized solution is 4:3:2, balancing four iron atoms and six oxygen atoms on each side.

Good uses

  • Check the coefficients in a chemistry assignment or laboratory reaction before using the equation in later calculations.
  • Obtain stoichiometric mole ratios for converting between known and required amounts of reactants or products.
  • Balance combustion equations or redox half-reactions, then verify conservation of elements and, where applicable, electric charge.

Limits and checks

  • The entered species must be chemically and syntactically correct. Balancing cannot repair a misspelled element symbol, an incorrect molecular formula, or ambiguous charge notation.
  • A balanced equation establishes conservation only. It does not show that the reaction occurs, identify a catalyst, predict reaction speed, or establish the equilibrium direction.
  • Some collections of species permit multiple independent coefficient relationships. In such an underdetermined equation, one displayed balanced set may not represent a chemically unique reaction.

Common questions

Can it balance redox half-reactions?

Yes, the tool supports redox half-reactions. Enter charges and electrons unambiguously, then check both atom totals and net charge in the result. The surrounding medium still matters: water, H+, or OH- may participate depending on whether conditions are acidic or basic, so an incomplete skeleton may not specify a unique half-reaction.

Does the balanced equation give the amount of product I will obtain?

No. Its coefficients give relative stoichiometric amounts, such as moles of one species per mole of another. Actual product quantity also depends on the starting amounts, limiting reactant, purity, reaction completion, and yield. Use the balanced coefficients as ratios, then perform the separate mass or mole calculation.

References and verification

The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.

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