Chemical equation balancer
Type an unbalanced equation. The page finds whole-number coefficients that conserve every atom, and shows the check.
- Coefficients and steps
- Free, no sign-up
Use an arrow, as in H2 + O2 -> H2O. Parentheses, charges and hydrates such as Ca(OH)2, Fe3+ and CuSO4·5H2O are welcome.
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How to use it
- Enter the equation with one arrow, such as H2 + O2 -> H2O.
- Read the atom equations, one row for each element.
- Use the coefficients on the balanced equation, then the atom check.
How a balance is found
Each formula is split into elements, with parentheses, brackets, charges and hydrate dots counted. The page builds one equation per element, and a charge equation when any formula carries a charge. It then finds the smallest positive whole numbers that satisfy every equation at once. Electrons can be written as e−. States such as (s), (l), (g) and (aq) are ignored, because they do not change the atoms.
Water is the sample: H2 + O2 -> H2O balances as 2, 1, 2, so the equation is 2 H2 + O2 -> 2 H2O. The check shows four hydrogens and two oxygens on each side. A mixture that contains more than one independent reaction still receives one valid set of coefficients, with a note that other whole-number sets also conserve the atoms.
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Questions
How does water balance?
H2 + O2 -> H2O becomes 2 H2 + O2 -> 2 H2O. The coefficients are 2, 1 and 2.
Can I use parentheses and charges?
Yes. Ca(OH)2, Fe2(SO4)3, Fe3+, OH− and CuSO4·5H2O are read as formulas. The charge is balanced along with the atoms.
What if the equation will not balance?
The working stops when no whole-number coefficients conserve every atom. Check the formulas and which side of the arrow each one is on.
Do I include coefficients myself?
You can. The page reads the formulas and computes the coefficients again, so a 2 already typed in front of H2O is replaced by the balanced value.