⚖️ Chemical Equation Balancer
Balance any chemical equation instantly, including redox and ionic equations with charges. See the atom count and mass check for every element.
Separate substances with +, sides with = or →. Case matters (Co is cobalt, CO is carbon monoxide). Write charges with ^, like Fe^3+ or SO4^2-, and electrons as e^-.
Coefficients: 1, 5, 3, 4 · Combustion
Atom check
| Element | Left | Right | Balanced |
|---|---|---|---|
| C | 3 | 3 | ✓ |
| H | 8 | 8 | ✓ |
| O | 10 | 10 | ✓ |
Mass check (conservation of mass)
| Substance | Molar mass (g/mol) | × coefficient |
|---|---|---|
| C3H8 | 44.097 | 44.097 |
| O2 | 31.998 | 159.990 |
| → CO2 | 44.009 | 132.027 |
| → H2O | 18.015 | 72.060 |
Reactants 204.087 g = products 204.087 g for the balanced amounts in moles.
What Chemical Equation Balancer Does
This chemical equation balancer finds the smallest whole-number coefficients for any reaction you type — from 4 Fe + 3 O₂ → 2 Fe₂O₃ to long redox equations — and proves the answer with an atom count for every element and a mass check that shows reactants and products weigh the same.
It is not a trial-and-error solver. Each element gives one equation (“iron atoms on the left equal iron atoms on the right”), charge gives another for ionic equations, and the system is solved exactly with fractions. That makes it reliable on equations that are painful by inspection, such as KMnO₄ + HCl, and lets it explain precisely why an equation cannot be balanced when a formula is wrong.
Parentheses, square brackets and hydrates are supported, charges are written with a caret (Fe^3+, SO4^2-) and electrons as e^-, so half-reactions balance too.
How to Use Chemical Equation Balancer
- Type the unbalanced equation, with + between substances and = or → between sides
- Write charges with ^ (Fe^3+) and electrons as e^-
- Read the balanced equation with the smallest whole-number coefficients
- Check the atom table — every element and the charge should match
- Use the mass table for stoichiometry, then copy the result
Formula Used by Chemical Equation Balancer
Balancing as linear algebra
A · x = 0, where A[element][substance] = atom count (negative for products), solved for the smallest positive whole-number x
Worked example
C₃H₈ + O₂ → CO₂ + H₂O
- C: 3a = c
- H: 8a = 2d
- O: 2b = 2c + d
- Set a = 1: c = 3, d = 4, b = (6 + 4) ÷ 2 = 5
Result: C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O
Charge balance (ionic equations)
Σ coefficient × charge on the left = Σ coefficient × charge on the right
Worked example
MnO₄⁻ + Fe²⁺ + H⁺ → Mn²⁺ + Fe³⁺ + H₂O
- Atoms alone leave the electron transfer undetermined
- Adding the charge row fixes it
Result: MnO₄⁻ + 5 Fe²⁺ + 8 H⁺ → Mn²⁺ + 5 Fe³⁺ + 4 H₂O (charge +17 on both sides)
Balanced Equations to Check Your Work
| Reaction | Balanced equation | Type |
|---|---|---|
| Rusting of iron | 4 Fe + 3 O₂ → 2 Fe₂O₃ | Synthesis |
| Burning propane | C₃H₈ + 5 O₂ → 3 CO₂ + 4 H₂O | Combustion |
| Burning glucose (respiration) | C₆H₁₂O₆ + 6 O₂ → 6 CO₂ + 6 H₂O | Combustion |
| Heating limestone | CaCO₃ → CaO + CO₂ | Decomposition |
| Aluminum in copper sulfate | 2 Al + 3 CuSO₄ → Al₂(SO₄)₃ + 3 Cu | Single replacement |
| Silver nitrate + salt | AgNO₃ + NaCl → AgCl + NaNO₃ | Double replacement |
| Copper in nitric acid | 3 Cu + 8 HNO₃ → 3 Cu(NO₃)₂ + 2 NO + 4 H₂O | Redox |
| Permanganate + HCl | 2 KMnO₄ + 16 HCl → 2 KCl + 2 MnCl₂ + 8 H₂O + 5 Cl₂ | Redox |
How to Read Your Result
Never change subscripts
Balancing changes only the coefficients in front of formulas. Changing H₂O to H₂O₂ to “fix” the oxygen count turns water into hydrogen peroxide — a different substance. If the only way to balance is to change a subscript, a formula is wrong.
More than one answer
H₂ + O₂ → H₂O + H₂O₂ can be balanced in infinitely many ways, because it is really two reactions happening together. Chemistry needs extra information (how much of each product forms) to choose one, so the tool reports it instead of guessing.
Reaction type labels
The label is a simple pattern match — one product means synthesis, one reactant means decomposition, an element swapping places means single replacement. Real reactions can fit more than one category, so treat it as a hint.
Limitations & Accuracy Notes
- Formulas must use element symbols; common names (water, table salt) and organic shorthand such as Et or Ph are not recognized.
- Charges must be written with ^; a charge typed without it, like Fe3+, cannot be told apart from a subscript followed by a plus sign.
- The balancer checks conservation only; it does not predict whether a reaction actually happens or what its products are.
Frequently Asked Questions
How do you balance a chemical equation?
How does this balancer work?
Why can’t my equation be balanced?
How do I enter charges and electrons?
Can I use parentheses, brackets and hydrates?
Why check the mass?
References & Further Reading
- Chemistry LibreTexts — Balancing Chemical Equations
- PhET Interactive Simulations — Balancing Chemical Equations — University of Colorado Boulder