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Chemical Equation Balancer

Balances any chemical equation in exact whole numbers and re-sums every element and the charge on both sides to prove the answer.

Calculators Nothing uploaded No sign-up Free, unlimited
Calculators tool
Use = or -> between the sides and + between species. Coefficients you type are ignored; working them out is the job. Ions work too: MnO4- + Fe2+ + H+ = Mn2+ + Fe3+ + H2O
Enter your figures and press Calculate.
In short Balancing an equation is not a puzzle to be guessed at — it is a linear algebra problem with a definite answer. Write one row per element, count each species positive on the left and negative on the right, and any set of coefficients the resulting matrix sends to zero is a balanced equation. Solved in exact fractions there is no rounding anywhere, and the smallest whole-number set is the standard form. Propane burning is C3H8 + 5O2 → 3CO2 + 4H2O, and both sides weigh 204.087 g/mol, because conserving every atom conserves the mass automatically. Permanganate and hydrochloric acid gives 2KMnO4 + 16HCl → 2KCl + 2MnCl2 + 8H2O + 5Cl2. Where the reaction involves ions, charge is conserved as well and becomes one more row in the same matrix: MnO4⁻ + 5Fe²⁺ + 8H⁺ → Mn²⁺ + 5Fe³⁺ + 4H2O carries a total charge of +17 on each side. Three outcomes are possible and they are genuinely different. Usually there is exactly one balancing. Sometimes there is none, because an element appears on one side only, and no arithmetic can fix that. And occasionally there is a whole family: C + O2 → CO + CO2 is balanced by any mixture of the two products, so the coefficients are decided by how the carbon burns and not by the equation. This tool distinguishes all three and says which one you have, rather than printing one member of a family as though it were the answer.

How to use the Chemical Equation Balancer

  1. Type the equation with = or -> between the sides.
  2. Leave the coefficients out — the tool works them out.
  3. Read the balanced equation, then check the table underneath, which re-sums every element from the answer.

About the Chemical Equation Balancer

Exact whole-number balancing for molecular and ionic equations, with a full conservation check.

What people use it for

  • Balancing an equation for homework and seeing why the coefficients come out as they do.
  • Balancing a redox half-reaction where charge has to be conserved as well as atoms.
  • Checking that an equation you were given is actually balanced.

Details

Propane combustionC3H8 + 5O2 → 3CO2 + 4H2O
Permanganate and HCl2KMnO4 + 16HCl → 2KCl + 2MnCl2 + 8H2O + 5Cl2
Iron rusting4Fe + 3O2 → 2Fe2O3
Ionic equationscharge is conserved too, as one more row
No balance existswhen an element appears on one side only
A family of balancesC + O2 → CO + CO2 has infinitely many
PrivacyEverything runs in your browser. Nothing you enter is sent anywhere
The table below the answer is not decoration. Every element is re-summed from the coefficients that came out, so a wrong answer could not pass its own check.

Where this tool stops

Balancing tells you what conserves atoms and charge. It says nothing about whether the reaction happens, how fast, in what conditions, or what else forms alongside. A balanced equation is arithmetic, not chemistry.

Frequently asked questions

How does equation balancing actually work?
Each element gives one equation in the unknown coefficients, so balancing is solving a small system of linear equations. This tool solves it in exact fractions and then scales to the smallest whole numbers, so the answer is exact rather than found by trial.
Can it balance redox and ionic equations?
Yes. Write the charges — MnO4-, Fe2+, H+ — and charge becomes one more conserved quantity alongside the elements. The total charge on each side is reported in the same table.
Why does it ignore the coefficients I typed?
Because working them out is what it does. Type the formulas alone; anything numeric at the front of a species is dropped, and the page says so when it happens.
What does "more than one independent balancing" mean?
That the equation as written has a family of correct answers rather than one. C + O2 = CO + CO2 is the standard example: any mixture of the two products conserves carbon and oxygen. Split it into separate equations if you need a single answer.
Why can some equations not be balanced?
Because an element appears on one side and not the other. Na + Cl2 = NaBr cannot balance at any coefficients, since there is no bromine on the left and no chlorine on the right. The tool names the element rather than just failing.
How do I write an ion so it is read correctly?
MnO4- and Fe2+ both work. Where a bare digit could be either a subscript or a charge, the rule used is the one chemists use — it is the charge only if what is left is a single element, so the 2 in Fe2+ is a charge and the 4 in MnO4- is a subscript. Use a caret, as in SO4^2-, whenever you want to be certain.
Is the Chemical Equation Balancer free, or is there a paid tier?
Free, unlimited, and no email address required. You can use it a hundred times a day and nothing changes.
Is my data uploaded anywhere?
No. The Chemical Equation Balancer runs entirely in your browser using JavaScript. Your input never reaches inputtesthub.com or any third party — open your browser's Network tab while you use it and you will see no request go out.
What do people use the Chemical Equation Balancer for most?
The jobs it is built for: balancing an equation for homework and seeing why the coefficients come out as they do. Balancing a redox half-reaction where charge has to be conserved as well as atoms. Checking that an equation you were given is actually balanced. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
Is there anything the Chemical Equation Balancer cannot do?
Balancing tells you what conserves atoms and charge. It says nothing about whether the reaction happens, how fast, in what conditions, or what else forms alongside. A balanced equation is arithmetic, not chemistry. Knowing where a tool stops being trustworthy matters more than the cases where it works.
What figures does the Chemical Equation Balancer work from?
Propane combustion is C3H8 + 5O2 → 3CO2 + 4H2O. Permanganate and HCl is 2KMnO4 + 16HCl → 2KCl + 2MnCl2 + 8H2O + 5Cl2. Iron rusting is 4Fe + 3O2 → 2Fe2O3. These are printed on the page itself, so you do not have to take them on trust.
Can I rely on this for exact work?
The calculation runs in double precision and the result is shown to ten significant figures, so converting a value and converting it back returns the original. What is displayed is rounded for readability; what is copied is not.

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