Education
Balancing Equations Calculator
Last updated: June 19, 2026
A balancing equations calculator is a chemistry tool that computes the stoichiometric coefficients required to satisfy the law of conservation of mass in a chemical reaction. By analyzing the input chemical equation, the utility sets up a system of linear equations representing the atom counts of each element on the reactant and product sides. It then solves for the lowest integer coefficients that balance the atoms of all elements. Chemistry students and researchers use this tool to determine correct reactant ratios.
Write a chemical equation in the usual notation (use -> or = between reactants and products). The calculator returns the balanced equation, the coefficients, and a per-element check that the atom counts match.
Quick Answer
Balance chemical equations instantly. Enter an unbalanced chemical equation to find the correct stoichiometric coefficients and see the balanced equation.
Chemical equation
Write each side as a sum of formulas separated by +. Use -> or = to separate reactants from products. Element symbols are case-sensitive (Na, not na).
e.g. H2 + O2 -> H2O
Notes
- Parentheses with subscripts work, e.g. Ca(OH)2.
- Coefficients in your input are ignored; the calculator solves them.
- Searches integer coefficients up to 12 per species, which covers the vast majority of high school and intro chemistry equations.
- For redox reactions that need much larger coefficients, split into half-reactions by hand.
Educational only. Do not use this output for laboratory dosing, scaling, or chemical safety decisions.
Balanced equation
2 H2 + O2 → 2 H2O
Each row of the atom-count table shows how many atoms of one element appear on the left and right after balancing. They should match.
Examples
H2 + O2 -> H2O
2 H2 + O2 → 2 H2O
C3H8 + O2 -> CO2 + H2O
C3H8 + 5 O2 → 3 CO2 + 4 H2O
Fe + Cl2 -> FeCl3
2 Fe + 3 Cl2 → 2 FeCl3
Al + CuSO4 -> Al2(SO4)3 + Cu
2 Al + 3 CuSO4 → Al2(SO4)3 + 3 Cu
How it works
Each chemical species expands into a count of atoms per element. Balancing means picking integer multipliers so that the sum of atom counts is the same on both sides for every element. The calculator searches integer combinations in order of total coefficient sum and returns the first solution it finds.
Conservation · Σ cᵢ × atomsᵢ(left) = Σ cⱼ × atomsⱼ(right)
Related chemistry and math calculators
- Molarity calculator for converting between molarity, moles, and volume in a solution.
- Scientific calculator for arithmetic with the balanced ratios.
- RREF calculator for balancing by setting up a linear system on the elemental coefficients.
- Limiting reactant calculator for the next step once you have the balanced coefficients and reactant amounts.
- Percent yield calculator for comparing actual vs theoretical product mass.
- Molecular weight calculator for molar mass of each species in the equation.
- Grams to moles calculator for the conversion step before applying coefficients.
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Frequently asked questions
Balancing means assigning whole-number coefficients to each reactant and product so that every element has the same total count on both sides. This reflects the law of conservation of mass: atoms are not created or destroyed during a chemical reaction.
It parses each side into species and counts atoms per element. Then it searches for the smallest set of positive integer coefficients (up to 12 per species) that makes every element balance. It returns the reduced form using the greatest common divisor.
Either the equation has a typo (mismatched element symbols, an element on one side that does not appear on the other), or the smallest balancing coefficients are larger than 12. In the second case, balance by half-reactions or solve the linear system by hand.
Yes. Ca(OH)2, Al2(SO4)3, and similar parenthesized groups are handled. Inner subscripts and the outer multiplier are combined correctly.
The calculator solves the coefficients itself. If you write 2H2 + O2 -> 2H2O, it parses the species (H2, O2, H2O) and finds the balancing coefficients fresh, returning the same answer.
No. The calculator is educational. Balanced equations describe stoichiometric ratios on paper but do not address rate, yield, energy, or any laboratory safety consideration. For real lab work, consult an instructor or a vetted procedure.
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