SMILES to IUPAC Name Converter
In short: Convert SMILES to an IUPAC name instantly, including stereo (E/Z, R/S). It is free, works in your web browser and needs no download.
Convert SMILES to IUPAC names for reports, assignments, naming checks, and chemical identifier workflows.
Tip: complex research codes such as calderasib or FMC-376 may resolve only if PubChem has a matching record.
Input and output formats
| Input: SMILES | Output: IUPAC name | |
|---|---|---|
| Full name | SMILES (Simplified Molecular Input Line Entry System) | IUPAC name |
| What it holds | Atoms, bonds, rings, charges and stereo as one line of text. No coordinates. | The systematic chemical name made with IUPAC naming rules. |
| File or form | .smi or plain text | Text |
File Format Explained
SMILES is a compact molecular line notation used for search, conversion, and cheminformatics workflows. It is optimized for machines rather than formal naming.
IUPAC names are systematic chemical names intended to describe compounds in formal language. They are useful in reports, assignments, publications, and naming checks.
One molecule may have multiple acceptable names or equivalent SMILES strings. Database-backed naming works best for recognized compounds with clear connectivity, charge, and stereochemistry.
How this SMILES to IUPAC converter works
The tool sends the SMILES string to PubChem's property lookup and displays the returned IUPAC name. You can also search PubChem first by compound name or CID, import the PubChem SMILES, and convert it automatically.
- Use SMILES for compact molecule identifiers.
- Use IUPAC names for formal reports, naming checks, and searchable chemical descriptions.
- If no result is found, verify stereochemistry, charges, salts, and unusual fragments in the SMILES input.
- For uncommon drug codes or research compounds, try both the code name and PubChem CID if available.
Related chemistry tools
Don't have the SMILES? Draw the molecule and get its IUPAC name directly.
Structure to IUPAC nameFrequently asked questions
How do I convert SMILES to an IUPAC name?
Paste the SMILES string and click Convert. MolDraw sends it to PubChem, which standardises the structure and returns its computed IUPAC name, including stereodescriptors.
Why does a SMILES with / or \ fail on other converters?
Slashes (E/Z double bonds) and # (triple bonds) break URL-based lookups. This converter sends SMILES in the request body, so stereo SMILES such as C/C=C/C(=O)O work and return (E)-but-2-enoic acid.
Can it name a molecule that is not in PubChem?
Usually not. Automatic naming relies on PubChem's database of over 100 million compounds. For new structures, name them by hand or name a close analogue and adapt it.
Can I draw a structure instead of typing SMILES?
Yes. Use the Structure to IUPAC Name tool, which has a built-in editor: draw the molecule and the name updates automatically.
Is the SMILES to IUPAC converter free?
Yes. It is free with no sign-up and runs in your browser.
Which name does it return for drugs like aspirin?
The systematic IUPAC name, e.g. 2-acetyloxybenzoic acid for aspirin, not the trade or common name.
Need to sketch the structure? Draw chemical structures online with MolDraw, a free online ChemDraw alternative.
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