Type a balanced molecular equation with phase labels and this tool dissociates every strong electrolyte into ions, cancels the spectator ions that appear unchanged on both sides, and shows you the net ionic equation — plus the complete ionic equation and the spectators it removed.
Molecular Equation
Include phase labels — (aq), (s), (l), (g) — after each formula. Use "->" or "=" as the reaction arrow.
"Auto-fill" assigns water to (l), common gases to (g), and applies solubility rules to decide (aq) vs. (s) for any formula you leave without a phase.
Example reactions
Net Ionic Equation
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Enter a balanced equation above to see the net ionic equation.
Complete Ionic Equation
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Every strong electrolyte dissociated into ions, before spectator ions are canceled.
Spectator Ions
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Ions that appear unchanged on both sides of the complete ionic equation, so they cancel out.
A molecular equation shows whole-formula reactants and products, but it hides what's actually happening in solution: strong electrolytes are dissolved as separate ions, not intact molecules.
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Walk-through
How to Use This Calculator
4 steps▸
1
Type a balanced molecular equation
Enter a balanced equation with a phase label — (aq), (s), (l), or (g) — after every formula, for example AgNO3(aq) + NaCl(aq) -> AgCl(s) + NaNO3(aq). Use "->" or "=" as the reaction arrow, or start from one of the example chips.
2
Choose how missing phases are handled
Leave "Use phases exactly as typed" selected if you already labeled every formula. Switch to "Auto-fill missing phases" if you left some off — the calculator assigns water to liquid, common gases to gas, and applies solubility rules to guess aqueous vs. solid for the rest.
3
Read the Net Ionic tab
The Net Ionic tab shows the headline result: the equation with spectator ions removed, plus a plain-language interpretation of what canceled and why.
4
Check Complete Ionic and Spectator Ions for the work
The Complete Ionic tab shows every strong electrolyte dissociated before cancellation, with a note on any species that stayed intact (and why). The Spectator Ions tab lists exactly which ions were removed.
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Reference
Formula & Methodology
2 formulas▸
Dissociation of strong electrolytes
AB(aq) -> A+(aq) + B-(aq)
Any strong electrolyte — a soluble ionic salt, a strong acid, or a strong base — that's dissolved in water (marked (aq)) separates completely into its cation and anion. Solids, liquids, gases, weak acids, and weak bases don't dissociate: they stay written as whole formulas even when they're technically in solution.
Canceling spectator ions
net ionic = complete ionic − spectator ions
A spectator ion is one that shows up with the same formula, charge, and coefficient on both the reactant side and the product side of the complete ionic equation — it's dissolved before the reaction and it's still dissolved after, unchanged. Removing every spectator ion from both sides leaves only the species that actually react: the net ionic equation.
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Glossary
Key Terms Explained
7 terms▸
Net ionic equation ↗The equation that remains after every spectator ion is removed from the complete ionic equation — it shows only the ions and molecules that actually participate in the chemical change.
Complete ionic equation ↗The molecular equation rewritten with every dissolved strong electrolyte split into its individual ions, before any spectator ions are canceled.
Spectator ion ↗An ion that appears in identical form — same formula, charge, and amount — on both sides of the complete ionic equation. It's present in solution but doesn't take part in the reaction.
Strong electrolyte ↗A substance that dissociates essentially completely into ions when dissolved in water: soluble ionic salts, strong acids (like HCl or HNO3), and strong bases (like NaOH or Ba(OH)2).
Dissociation ↗The process of a compound separating into its constituent ions when it dissolves. Strong electrolytes dissociate completely; weak electrolytes like acetic acid dissociate only partially and are written as intact molecules in ionic equations.
Precipitate ↗An insoluble solid that forms when two aqueous solutions are mixed and their ions combine into a compound the solubility rules classify as insoluble — marked (s) in the equation.
Solubility rules ↗A set of qualitative guidelines (all Group 1 and ammonium salts are soluble, most nitrates are soluble, most carbonates are insoluble, and so on) used to predict whether an ionic compound dissolves in water or precipitates as a solid.
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Scenarios
Real-World Examples
3 worked examples▸
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Chem 101 student
Precipitation reaction
Equation AgNO3(aq) + NaCl(aq) -> AgCl(s) + NaNO3(aq)Mode Use phases as typed
Both reactants are soluble salts, so AgNO3 and NaCl fully dissociate into Ag+, NO3-, Na+, and Cl-. AgCl is insoluble (silver halides are an exception to the "halides are soluble" rule), so it stays intact as a solid. Na+ and NO3- appear unchanged on both sides and cancel as spectators, leaving the net ionic equation Ag+(aq) + Cl-(aq) -> AgCl(s) — the actual reaction is silver and chloride ions combining into a precipitate.
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Lab TA
Acid-base neutralization
Equation HCl(aq) + NaOH(aq) -> NaCl(aq) + H2O(l)Mode Use phases as typed
HCl is a strong acid and NaOH is a strong base, so both dissociate completely: H+, Cl-, Na+, and OH-. Water doesn't dissociate (it's the solvent itself), and NaCl on the product side redissolves into Na+ and Cl-. Na+ and Cl- are identical on both sides and cancel, leaving H+(aq) + OH-(aq) -> H2O(l) — every strong acid/strong base neutralization boils down to this same net ionic equation.
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Exam reviewer
All spectators — no net reaction
Equation NaCl(aq) + KNO3(aq) -> NaNO3(aq) + KCl(aq)Mode Use phases as typed
Every product here (NaNO3, KCl) is soluble, so nothing precipitates and every ion — Na+, Cl-, K+, NO3- — shows up unchanged on both sides. With all four species canceling as spectators, there's no net ionic equation left: mixing these two solutions doesn't produce a chemical reaction, just a mixture of the same four ions already in solution.
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Reference
Cite This Calculator
APA & MLA▸
Use either format to cite this calculator in a paper, report, or resource list.
A molecular equation shows whole-formula reactants and products, but it hides what's actually happening in solution: strong electrolytes are dissolved as separate ions, not intact molecules. This calculator dissociates every strong electrolyte, cancels the ions that don't participate in the reaction, and shows you the net ionic equation — the version that reflects what's really reacting.
How the Net Ionic Equation Calculator works
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Starting from your balanced molecular equation, the calculator checks each formula's phase label. Anything marked (aq) is tested against a recognized set of strong electrolytes — soluble ionic salts, strong acids, and strong bases — using standard solubility rules to decide which salts actually dissolve. A recognized strong electrolyte splits into its cation and anion, each carrying the original formula's coefficient; everything else (solids, liquids, gases, weak acids, weak bases, and molecular compounds) is left as a whole formula. That expanded equation is the complete ionic equation.
From there, the calculator looks for any ion that appears with the exact same formula, charge, and coefficient on both the reactant and product side. Those are spectator ions — present before and after the reaction, unchanged — and removing them from both sides leaves the net ionic equation.
Inputs and what they mean
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Balanced molecular equation is the whole-formula equation you'd normally write for the reaction, with a phase label — (aq), (s), (l), or (g) — after every formula. The calculator assumes the equation is already balanced; it doesn't balance coefficients for you.
Missing phase labels controls what happens if you skip a phase label. "Use phases exactly as typed" treats a missing label as an error so you can fix it. "Auto-fill missing phases" instead assigns water to (l), a short list of common gases to (g), and applies solubility rules to the rest to guess (aq) vs. (s) — useful for a quick check, but always verify an auto-filled phase against your actual reaction conditions.
Limits and edge cases
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The ion tables and solubility rules here cover the compounds that show up in a standard general-chemistry course — common metal cations, polyatomic ions, and the textbook solubility-rule exceptions. Less common ions, coordination complexes, and organic acids beyond the handful of curated weak acids may not be recognized; when that happens, the calculator leaves the formula intact rather than guessing at a split, which is the safer failure mode. It also doesn't balance unbalanced equations or verify that your reaction is chemically valid — it only dissociates, applies solubility rules, and cancels spectators from what you enter.
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Questions
Frequently Asked Questions
6 questions▸
What are the steps to find a net ionic equation?+
Dissociate every strong electrolyte marked (aq) into its ions to get the complete ionic equation, then cancel any ion that appears with the same formula, charge, and coefficient on both sides. What's left is the net ionic equation.
What exactly is a spectator ion?+
A spectator ion is an ion that's dissolved in solution before the reaction and still dissolved, unchanged, after it — it appears identically on both the reactant and product side of the complete ionic equation, so it doesn't represent an actual chemical change and gets removed.
Do solids, liquids, and gases get dissociated?+
No. Only aqueous strong electrolytes dissociate. Solids (s), liquids (l) like water, and gases (g) are written as whole formulas in both the complete and net ionic equations because they aren't present in solution as separate ions.
Why doesn't a weak acid like acetic acid dissociate?+
Weak acids and weak bases only partially ionize in water — most of the molecule stays intact — so by convention they're written as whole formulas in ionic equations even when their phase is (aq). This calculator recognizes common weak acids (acetic, carbonic, phosphoric, hydrofluoric, and others) and keeps them intact automatically.
How does the calculator decide what's soluble?+
It applies the standard qualitative solubility rules taught in general chemistry: Group 1 and ammonium compounds are always soluble, most nitrates and acetates are soluble, most chlorides/bromides/iodides are soluble except with silver, lead, and mercury(I), most sulfates are soluble with a handful of exceptions, and most hydroxides, carbonates, phosphates, and sulfides are insoluble except with Group 1 or ammonium.
Why do I need to include phase labels?+
The phase label is what tells the calculator whether a species is actually dissolved and available to dissociate. Without it, there's no way to distinguish, say, aqueous BaSO4 from solid BaSO4 — so "Use phases exactly as typed" mode requires a label on every formula, and "Auto-fill" mode exists specifically to fill in labels you leave off.
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