thermo is an open-source software for engineers, scientists, technicians and anyone trying to understand the universe in more detail. It facilitates the retrieval of constants of chemicals, the calculation of temperature and pressure dependent chemical properties (both thermodynamic and transport), the calculation of the same for chemical mixtures (including phase equilibria), and assorted information of a regulatory or legal nature about chemicals. The thermo library depends on the SciPy library to provide numerical constants, interpolation, integration, differentiation, and numerical solving functionality. thermo all operating systems which support Python, is quick to install, and is free of charge. thermo is designed to be easy to use while still providing powerful functionality. If you need to know something about a chemical, give thermo a try.