InChIKey to InChI Converter
In short: Resolve an InChIKey into a full InChI string using public chemistry identifiers. It is free, works in your web browser and needs no download.
Resolve an InChIKey into a full InChI string through PubChem.
Input and output formats
| Input: InChIKey | Output: InChI | |
|---|---|---|
| Full name | InChIKey | InChI (IUPAC International Chemical Identifier) |
| What it holds | A 27 character hash of the InChI, made for web and database search. It cannot be turned back into a structure without a lookup database. | A layered text identifier built from the structure. The standard InChI is the same in every program. |
| File or form | Text like XXXXXXXXXXXXXX-YYYYYYYYYY-Z | Text starting with InChI=1S/ |
File Format Explained
InChIKey is a fixed-length hashed key made from an InChI. It is excellent for searching databases, but the full InChI cannot be mathematically recovered from the key alone.
InChI is the full International Chemical Identifier and carries readable structural layers. This converter resolves the InChIKey through PubChem when a matching record is available.
If no match is found, the compound may be absent from the lookup database or the InChIKey may refer to a different protonation, stereochemical, or isotopic form.
How this lookup works
An InChIKey is a one-way hash, so it cannot be decoded into a structure directly. This tool resolves the key against a chemical database and returns the full InChI of the matching record. If no database knows the compound, there is no way to recover the structure from the key alone.
How to use it
- Paste a 27-character InChIKey in the format XXXXXXXXXXXXXX-XXXXXXXXXX-X.
- Run the lookup.
- Use the InChI in other tools, or convert onward with InChI to SMILES.
Example
Caffeine's InChIKey RYYVLZVUVIJVGH-UHFFFAOYSA-N resolves to InChI=1S/C8H10N4O2/c1-10-4-9-6-5(10)7(13)12(3)8(14)11(6)2/h4H,1-3H3.
Troubleshooting
- Check for missing hyphens or extra spaces copied from a PDF.
- Newly made or proprietary compounds may not be in public databases.
- If you only know the first 14-character block, search it in a database to list all stereoisomers that share that skeleton.
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