Write the layers yourself, and be markedWrite a formula, a connection layer, a hydrogen layer or a whole identifier, and the engine checks it against what it generates for the same structure — so the marking is the real answer, not a stored string.Convert a structure to its InChI and InChIKey and back, convert a whole CSV, XLSX or SDF file, learn how the identifier is derived, and practise writing its layers. The InChI engine is WebAssembly running in your browser, so the tool needs JavaScript — and nothing you open ever leaves your machine.

Convert — a structure in, an InChI out

Batch — a whole CSV, XLSX or SDF file

Tutorial — how an InChI is derived

Exercises — write the layers yourself

Cheatsheet — every layer in a table

Tests — the IUPAC regression corpora

Download — take the engine away

About, and what to cite

Our other tools

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surge.cheminfo.org — Every constitutional isomer of a molecular formula.

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lcao.cheminfo.org — Combine atomic orbitals into molecular ones.

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powerpoint.cheminfo.org — Put a live tool on a slide, from the link its Share button gives.