The Open Chemistry Database (OChemDb) is a new free online portal which uses an appropriately designed database of already solved crystal structures. It makes freely available computational and graphical tools for searching and analysing crystal-chemical information of organic, metal–organic and inorganic structures, and providing statistics on desired bond distances, bond angles, torsion angles and space groups. Atom types have been classified by an identifier code containing information about the chemical topology and local environment. The crystallographic data used by OChemDb are acquired from the CIFs contained in the free small-molecule Crystallography Open Database (COD). OChemDb offers easy-to-use and intuitive options for searching. It is updated by following the continuous growth of information stored in the COD. It can be of great utility for structural chemistry, in particular in the process of determination of a new crystal structure, and for any discipline involving crystalline structure knowledge. The use of OChemDb requires only a web browser and an internet connection. Every device (mobile or desktop) and every operating system is able to use OChemDb by accessing its web page. Examples of application of OChemDb are reported.