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Chemical Equation Balancer

Balance chemical equations instantly and check every element with an atom count table. Supports brackets and hydrates. Free balancer for GCSE, AP Chemistry, IB and NEET.

Balanced equation

4 Fe+3 O2→2 Fe2O34\,\mathrm{Fe} + 3\,\mathrm{O_{2}} \rightarrow 2\,\mathrm{Fe_{2}O_{3}}

4Fe + 3O2 → 2Fe2O3

Atom count check

ElementLeft (reactants)Right (products)Balanced
Fe44✓
O66✓
  1. 1

    List the elements and write unknown coefficients

    Elements present: Fe, O. Give each species an unknown coefficient.

    a Fe+b O2→c Fe2O3a\,\mathrm{Fe} + b\,\mathrm{O_{2}} \rightarrow c\,\mathrm{Fe_{2}O_{3}}
  2. 2

    Write an atom-balance equation for each element

    Atoms of each element on the left must equal atoms on the right.

    Fe:  a=2cO:  2b=3c\begin{aligned} \mathrm{Fe}: & \; a = 2c \\ \mathrm{O}: & \; 2b = 3c \end{aligned}
  3. 3

    Solve the system

    Set c = 1 and solve the linear equations exactly (Gaussian elimination with fractions).

    a=2,  b=32,  c=1a = 2,\; b = \tfrac{3}{2},\; c = 1
  4. 4

    Convert to the smallest whole numbers

    Multiply every coefficient by 2 to clear the fractions (and divide out any common factor).

    a=4,  b=3,  c=2a = 4,\; b = 3,\; c = 2
  5. 5

    Verify the atom counts

    Count every element on both sides of the balanced equation.

    Fe:  4=4  ✓O:  6=6  ✓\begin{aligned} \mathrm{Fe}: & \; 4 = 4 \;\checkmark \\ \mathrm{O}: & \; 6 = 6 \;\checkmark \end{aligned}
  6. 6

    Balanced equation

    4 Fe+3 O2→2 Fe2O34\,\mathrm{Fe} + 3\,\mathrm{O_{2}} \rightarrow 2\,\mathrm{Fe_{2}O_{3}}

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FAQ

How does balancing work?

Atoms of each element must be equal on both sides; the tool solves for the smallest whole-number coefficients.

How do I type the equation?

Use = or -> between sides and + between species, e.g. C3H8 + O2 -> CO2 + H2O.

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