Equation Balancer
A chemical equation is a promise: no atom is created or destroyed. Balancing is just making the promise true — the same atoms on both sides, only rearranged. Nudge the numbers, watch the tally even out, or let it solve itself.
The one rule: conservation of mass
The little numbers inside a formula (the subscript 2 in H2O) can never change — that would make a different substance. So the only thing you're allowed to adjust is the big number in front, the coefficient, which says how many of that molecule take part. Balance the equation and every column in the atom table matches.
The five reaction types
- Synthesis — two or more things combine into one (H2 + O2 → H2O).
- Decomposition — one compound breaks apart (KClO3 → KCl + O2).
- Combustion — a fuel burns in oxygen to give CO2 and water (CH4 + O2 → CO2 + H2O).
- Single replacement — one element pushes another out of its compound (Zn + HCl → ZnCl2 + H2).
- Double replacement — two compounds swap partners (AgNO3 + NaCl → AgCl + NaNO3).
Balance any reaction above and this tool names its type for you.
Part of SpecEnvoy Chemistry — build the reactants atom-by-atom in the Atom Builder, or see their shapes in the Molecule Lab.