MolChart – AI Chemical Structure Editor

Describe a molecule or an edit in plain English. MolChart draws it, verifies it against PubChem, and exports SMILES, MOL, PNG or SVG. Free, in the browser, no account needed.

What you can do

  • Draw molecules from words: “draw caffeine”, “aspirin”, “a benzene ring with a nitro group para to a methoxy”.
  • Edit by instruction: “add a chlorine at position 4”, “replace the ester with an amide”, “make the stereocentre R”.
  • Import and export: SMILES, MOL files, chemical names in; SMILES, MOL, PNG, SVG out.
  • Analyze: structure → IUPAC name, molecular formula and properties, stereochemistry, valence checks, PubChem lookup.
  • Verified results: every AI edit is checked against the canvas and against PubChem before it is accepted.
  • Reactions and 3D: reaction schemes with arrows and text; 3D view of any structure.
  • Works with AI assistants: available as a ChatGPT app and as an MCP server at molchart.com/mcp.

Frequently asked questions

Is MolChart free?

Yes: 200 AI messages per browser without an account, 1,000 per month with a free account, and 5,000 per month for members ($30/month).

Is MolChart a ChemDraw alternative?

For drawing and exporting 2D structures and simple reaction schemes in the browser, yes. It is AI-driven: you tell it what to draw instead of placing atoms and bonds by hand.

Which browsers are supported?

Any modern desktop or mobile browser with JavaScript enabled.