Enter a balanced reaction to get the complete ionic equation, spectator ions, and the final net ionic equation with plain-language split rules.
Advanced options
How to use our Net Ionic Equation Calculator
- Paste or type your reaction into Chemical equation, including states like (aq), (s), (l), or (g) when you know them.
- Choose What are you entering? so the calculator knows whether to start from a balanced molecular equation or a complete ionic equation.
- Set If some states are missing to either require states or infer common ones and mark assumptions, then open Advanced options if you want to change coefficient reduction or how weak acids and weak bases are treated.
- Click Calculate and read Net ionic equation first, then check Complete ionic equation, Spectator ions, and Why each species was split or kept together to see each step.
- Sanity-check the result: make sure atoms and total charge match on both sides, and if Assumptions or fixes used shows inferred states, confirm those states match your class rules.
Definitions
Chemical equation: The reaction you enter, with reactants on the left and products on the right.
Complete ionic equation: A version of the reaction where strong electrolytes in water are written as separate ions, while solids, liquids, gases, and weak electrolytes stay together [1].
Net ionic equation: The simplified equation after unchanged ions are removed, showing only the species that actually change [1].
Spectator ions: Ions that appear unchanged on both sides of the complete ionic equation, so they cancel out [1].
Strong electrolyte: A substance that separates into ions in water, such as a soluble ionic compound or a strong acid.
Weak acid or weak base: A substance that is often kept as one whole formula in net ionic work unless your class uses a different rule.
Aqueous (aq): Dissolved in water. This state often matters when deciding whether a substance should split into ions.
Common mistakes and quick fixes
Mistake: Leaving states out of Chemical equation while expecting an exact Net ionic equation .
Fix: Add (aq), (s), (l), or (g), or use If some states are missing set to infer and then review Assumptions or fixes used .
Mistake: Choosing the wrong option in What are you entering? , such as pasting ions while molecular mode is selected.
Fix: If your equation already shows ions like Na+(aq) or Cl-(aq), switch What are you entering? to complete ionic equation.
Mistake: Entering an unbalanced reaction and expecting the Complete ionic equation to come out right.
Fix: Balance the reaction first in Chemical equation so the same number of each atom appears on both sides.
Mistake: Splitting water, solids, gases, or weak electrolytes when reading Why each species was split or kept together .
Fix: Keep species like H2O(l), precipitates such as AgCl(s), and weak acids or weak bases together unless your class specifically says otherwise.
Mistake: Canceling ions that are not truly identical when checking Spectator ions .
Fix: Only cancel a species if formula, charge, state, and amount match on both sides; an aqueous ion does not cancel with a solid form of that same substance.
Mistake: Thinking a blank-looking result means the calculator failed.
Fix: Read What happens and Net ionic equation ; if every aqueous ion cancels, the correct result may be no net ionic reaction.
Limitations & Key Assumptions / Boundary Conditions
- The calculator depends on a correctly written reaction. If the entered reaction is unbalanced or uses unsupported formulas, it may stop and ask for a cleaner equation.
- States matter. When If some states are missing is set to require states, missing states block the result. When inference is allowed, the answer can depend on classroom-style assumptions.
- Weak acid and weak base treatment can differ by teacher or textbook. The How to treat weak acids and weak bases setting changes how those species are written.
- Only identical species cancel. A substance does not count as a spectator if its state, charge, or coefficient changes between sides.
- Some complex ions, coordination compounds, unusual redox reactions, or ambiguous formulas may be outside the parser and may return an unsupported message instead of a full result.
- If all aqueous ions cancel, the correct output is No net ionic reaction. That does not mean the calculator is broken.
Methodology
How the calculator builds the answer
First, it reads the reaction from Chemical equation and checks that there is one arrow, at least one reactant, and at least one product. If you choose molecular mode, the reaction must already be balanced before ionic steps are done. If you choose complete ionic mode, the calculator starts from the ions you typed.
Complete ionic equation = split strong electrolytes in water into ions; keep solids, liquids, gases, weak electrolytes, and nonelectrolytes together.
For each reactant and product, the calculator fills the Why each species was split or kept together table. It gives a plain reason such as strong acid in water, aqueous ionic compound, solid precipitate, liquid water, gas, or weak electrolyte kept whole.
Spectator ion cancellation = remove species that appear on both sides with the same formula, charge, state, and matching shared amount.
After the complete ionic equation is written, unchanged ions are canceled to produce the Net ionic equation. If the same ion appears on both sides but in different amounts, only the shared amount is canceled. If nothing remains after cancellation, the result is reported as no net ionic reaction rather than leaving the answer blank [1].
Reduced net ionic coefficients = remaining coefficients divided by their greatest common divisor, if reduction is turned on.
Mini-example
Example input: AgNO3(aq) + NaCl(aq) -> AgCl(s) + NaNO3(aq).
The strong aqueous compounds AgNO3(aq), NaCl(aq), and NaNO3(aq) are split into ions. The solid AgCl(s) stays together.
Complete ionic: Ag+(aq) + NO3-(aq) + Na+(aq) + Cl-(aq) -> AgCl(s) + Na+(aq) + NO3-(aq)
Na+(aq) and NO3-(aq) appear unchanged on both sides, so they are spectator ions and cancel.
Net ionic: Ag+(aq) + Cl-(aq) -> AgCl(s)
This tells you a precipitate forms, because dissolved ions combine to make a solid.
Assumptions used by the rules
The calculator follows the standard classroom idea that strong soluble ionic compounds and strong acids in aqueous solution are written as ions, while weak acids, weak bases, water, gases, and insoluble solids are usually kept together [1]. If state inference is enabled, inferred states are listed in Assumptions or fixes used so you can check whether they match your assignment. The calculator also checks that the final ionic result stays balanced for both atoms and total charge before showing it.