InChI to SMILES Converter
In short: Convert InChI identifiers to canonical SMILES strings. It is free, works in your web browser and needs no download.
Convert InChI strings from literature and databases into SMILES format.
Input and output formats
| Input: InChI | Output: SMILES | |
|---|---|---|
| Full name | InChI (IUPAC International Chemical Identifier) | SMILES (Simplified Molecular Input Line Entry System) |
| What it holds | A layered text identifier built from the structure. The standard InChI is the same in every program. | Atoms, bonds, rings, charges and stereo as one line of text. No coordinates. |
| File or form | Text starting with InChI=1S/ | .smi or plain text |
File Format Explained
InChI is the IUPAC International Chemical Identifier. It is layered, deterministic, and useful for describing molecular formula, connectivity, hydrogens, charge, stereochemistry, and isotopes.
SMILES is shorter and easier to paste into many drawing, search, and cheminformatics tools. Converting InChI to SMILES is helpful when a database gives InChI but your workflow expects SMILES.
Different services may return different canonical SMILES for the same InChI. Treat equivalent SMILES strings as valid if they describe the same molecule.
When to convert InChI to SMILES
InChI is excellent for identifying a compound unambiguously, but most drawing programs, cheminformatics scripts, and search boxes expect SMILES. Converting lets you take an identifier from a database record or a paper's supplementary data and turn it into something you can edit and draw.
How to use it
- Paste a full InChI string, including the
InChI=1S/prefix. - Convert, then copy the SMILES output.
- Paste the SMILES into MolDraw to see and edit the structure.
Example
Ethanol: InChI=1S/C2H6O/c1-2-3/h3H,2H2,1H3 becomes CCO. The InChI lists the formula, the connectivity layer (atoms 1–2–3), and where the hydrogens are; SMILES expresses the same molecule in three characters.
FAQ
Will stereochemistry be kept? If the InChI contains stereo layers (/t, /m, /s or /b), they are translated into SMILES @ or / and \ symbols. Why is my SMILES different from another tool's? One molecule can have several valid SMILES; compare them by converting both to an InChIKey with SMILES to InChIKey.
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