Supported local records
Stored diagrams, electron counts, geometry, angles, hybridization, molar mass and composition.
Free Lewis structure calculator
Lewis Structure Generator & Lewis Dot Calculator
Enter a molecule or ion to generate its Lewis structure and check the key answer details: valence electrons, lone pairs, formal-charge guidance, VSEPR geometry, bond angle and hybridization.
1Enter a formulaExample: H2O or NO3-
2Generate the resultSee the stored diagram
3Open the guideCheck electrons and charges
Free · No signup · PNG & SVG downloads
Valence electrons · Lone-pair guidance · Geometry · Bond angles
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Result: Water (H₂O)
Local Lewis recordRepresentationReviewed educational representation with a dedicated guide
1Confirm the total valence-electron budget.
2Check lone pairs, formal charges and resonance.
3Use VSEPR to interpret the 3D geometry.
Educational reference only. Verify important answers with course materials. Unsupported inputs may show a PubChem 2D structure reference, which is not necessarily a Lewis dot diagram.
Need the steps?Open the molecule guide for electron counting, lone-pair placement, formal charges, resonance and geometry.
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Try Common Lewis Structures
Select a supported example to generate its stored diagram and molecular properties.
Browse all supported molecules and detailed guides →auto_stories
Learn the Method with Pictures
The generator gives you a result. The illustrated guide shows why that result is correct, one electron move at a time.
Start with the budget
Count every valence electron
Fix the total before drawing so dots and bonds cannot appear from nowhere.
Find the problem
Check the central atom
Using all electrons does not guarantee a valid structure. Verify octets.
Verify the answer
Check charges and geometry
Finish by confirming electron totals, formal charges and VSEPR shape.
Six illustrated steps, one complete worked example
Follow CO₂ from the periodic table to the final O=C=O structure, then apply the same method to NH₃ and H₂O.
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Step-by-Step Lewis Structure Guides
Each guide explains electron counts, connectivity, lone pairs, formal charges, resonance and molecular geometry for one compound.
CCl4 Lewis structureLone pairs, tetrahedral geometry and polarityCO2 Lewis structureDouble bonds, 180° geometry and polaritySO2 Lewis structureResonance, formal charges and bent geometryH2O Lewis structureLone pairs, steric number and bent geometryCH3OH Lewis structureElectron geometry around carbon and oxygenSF6 Lewis structureOctahedral geometry, bond angles and hybridizationPCl5 Lewis structureExpanded valence and trigonal-bipyramidal geometryO3 Lewis structureResonance contributors and formal chargesNF3 Lewis structureElectron geometry, molecular shape and polarityNH3 Lewis structureNitrogen lone pair and pyramidal geometryCH4 Lewis structureFour single bonds and tetrahedral geometryBF3 Lewis structureIncomplete-octet exceptionHNO3 Lewis structureOxyacid resonance and charges
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Learn, Generate and Practice Lewis Structures
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Illustrated generator with steps
Follow an illustrated method for electron counting, skeleton selection, lone pairs, multiple bonds and final checks.
quizPractice problems
Work through randomized formulas, reveal hints and compare your drawing with the detailed answer guides.
balanceFormal charges and resonance
Learn the formal-charge equation, compare candidate structures and draw resonance contributors correctly.
electric_boltIons and ionic compounds
Understand brackets, total charge, electron addition or removal and the limits of molecular Lewis diagrams.
hubOrganic chemistry structures
Review carbon valence, condensed formulas, multiple bonds, functional groups and formula ambiguity.
view_in_arLewis structure vs 3D geometry
See why a Lewis diagram is 2D and how VSEPR converts electron domains into a three-dimensional molecular shape.
What the generator gives you
Lewis Structure Answers with Chemistry Context
For reviewed and supported compounds, the generator combines the Lewis diagram with the electron count, molecular geometry, bond angle, hybridization and a direct step-by-step guide.
If a formula is not in the reviewed Lewis library, the tool clearly labels any external 2D reference so it is not confused with a Lewis dot structure.
Free downloads
Save the displayed Lewis structure as a PNG or SVG file directly in the browser.
Molecular geometry
Available records include VSEPR geometry names and representative bond angles.
Transparent limits
Unsupported, ambiguous and model-dependent cases are documented instead of being presented as guaranteed answers.
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Explore Lewis Structure Calculators and Topic Hubs
Move from a broad chemistry question to a focused calculator, comparison or practice page.
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Polyatomic ion structures
Compare charge, electron counts, resonance and reviewed ion guides.
sync_altResonance examples
Understand contributors, formal charges and the resonance hybrid.
errorOctet rule exceptions
Review incomplete octets, radicals and expanded-valence models.
calculateValence electron calculator
Build the electron budget for simple molecules and ions.
balanceFormal charge calculator
Calculate FC from valence, nonbonding and bonding electrons.
assignmentWorksheet with answers
Practice common structures and reveal checked answer summaries.
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Frequently Asked Questions
Is this Lewis structure generator free and online?
Yes. It runs in a browser, requires no account and is free to use. Generated diagrams can be downloaded as PNG or SVG.
Does the Lewis dot structure generator show steps?
Yes for reviewed molecules: the result links directly to a worked guide covering electron counting, bonds, lone pairs, formal charges, resonance when relevant and geometry. The illustrated six-step guide explains the general method.
Does it generate 3D Lewis structures?
No. Lewis structures are two-dimensional electron diagrams. The site provides geometry names and bond angles for supported records, but it is not an interactive 3D molecular viewer.
Can it generate resonance structures and formal charges?
The local generator may display one stored representation. The formal-charge and resonance guide explains how to evaluate and draw all required contributors.
Does it support ionic compounds?
It supports selected polyatomic ions and charged species. A Lewis structure for an ionic compound may require separate bracketed ions rather than one covalent molecular diagram.
Does it support organic chemistry Lewis structures?
Selected organic molecules are stored locally, but one molecular formula can represent several isomers. Use the organic chemistry guide to understand connectivity and formula ambiguity.
Are PubChem results Lewis dot structures?
Not necessarily. PubChem usually returns a conventional 2D chemical structure and may omit lone pairs, electron dots and formal charges.