About the Chemical Equation Balancer
Chemical Equation Balancer finds the whole-number coefficients that balance a chemical equation. Type the reactants and products with an arrow, such as Fe + O2 -> Fe2O3, and the page solves for the smallest whole numbers so that every element appears the same number of times on both sides: 4Fe + 3O2 → 2Fe2O3. It handles brackets such as Ca(OH)2, hydrates such as CuSO4.5H2O and equations with many substances, and it says clearly when an equation cannot be balanced or has more than one solution. Ionic charges are not supported.
Updated October 2026
How to use the Chemical Equation Balancer
- 1Type the unbalanced equation with -> or = for the arrow.
- 2Separate substances with a plus sign and use capital letters for elements.
- 3Read the balanced equation and the coefficient of each substance.
- 4Copy the balanced equation.
- 5Fix a typo if the page says an element appears on only one side.
Why equations need balancing
Atoms are not created or destroyed in a chemical reaction, so the same number of each kind of atom must be present before and after. A coefficient in front of a formula multiplies the whole formula. For example 2H2 + O2 → 2H2O has four H atoms and two O atoms on each side.
How to check the answer
Count each element on both sides. Multiply the coefficient by every subscript in its formula, and for brackets multiply by the number outside as well. Calcium hydroxide, Ca(OH)2, has one Ca, two O and two H. The page lists the coefficient of each substance so you can do this check in seconds.
- C3H8 + 5O2 → 3CO2 + 4H2O (burning propane)
- Fe + O2 → Fe2O3 needs 4, 3 and 2
- 2KMnO4 + 16HCl → 2KCl + 2MnCl2 + 8H2O + 5Cl2
Learning to balance by hand
Start with the element that appears in the fewest substances, balance one element at a time and leave hydrogen and oxygen until last. Use fractions if you must and then clear them by doubling. This page is best used to check your own attempt and to see the method in action.
Related tools
Find molar masses with the Molecular Weight Calculator, convert grams and moles with the Mole Calculator and the success of a reaction with the Percent Yield Calculator. The Solution Concentration Calculator and the Dilution Calculator cover the next steps.
Features
- Solves for the smallest whole numbers
- Brackets, hydrates and many substances
- Clear messages for impossible equations
- Shows coefficients for each substance
- Uses exact fractions, no rounding
- Private: nothing is uploaded
Frequently asked questions
How do I balance a chemical equation?
Make the number of atoms of each element equal on both sides by putting whole-number coefficients in front of the formulas. Never change the small numbers inside a formula.
What does the page do?
It writes one equation per element, solves them exactly and scales the answer to the smallest whole numbers.
Why does it say an element appears on only one side?
Matter cannot appear or vanish, so every element in the reactants must also be in the products. Check the formulas for a typo or a missing substance.
What if it says there is more than one way to balance?
Some sets of substances can react in different proportions at once. Split the equation into separate reactions.
Does it balance ionic and redox equations?
It balances atoms only. For charges or half-reactions, balance the atoms first and add electrons by hand.
How do I write hydrates?
Use a dot: CuSO4.5H2O. A multiplication dot (·) also works.
Does capitalisation matter?
Yes. Co is cobalt and CO is carbon monoxide. Elements start with a capital letter followed by a small one.
Is my equation uploaded?
No. It is solved in your browser.