Chempirical is a browser-based collection of free chemistry tools designed to support practical work at the bench, with no account required. Its tools help chemists draw and inspect molecular structures, calculate properties, interpret spectra, plan reactions and prepare solutions. The Covalent structure editor checks valence and stereochemistry as users draw, while Signum opens and processes NMR, IR, UV-Vis and mass spectra. Users can predict NMR shifts and convert common spectrum files, including JCAMP-DX, SPC and CSV.

For reaction planning, Chempirical offers reaction scaling, stoichiometry and equation balancing, alongside tools for limiting reagents and theoretical yields. Its distillation and physical-data resources include pressure-dependent boiling points, vapour-pressure curves and fraction predictions. Additional utilities cover pH, buffers, molar mass, drug-likeness and periodic-table data. A compound-list tool organizes names, CAS numbers or SMILES with properties and GHS hazards, and a chemical-inventory tool supports stock, storage and expiry tracking. The site also provides access to a database of nearly 49,000 compounds and publishes articles on chemistry methods, spectra and file formats.