Combustion Toolbox (CT) models thermodynamic properties of the gaseous species with the ideal gas equation of state (EoS). Written in MATLAB, this thermochemical code is modular and has three main modules: CT-EQUIL, CT-SD, and CT-ROCKET. CT-EQUIL computes the composition at the equilibrium of multi-component gas mixtures that undergo canonical thermochemical transformations from an initial state (reactants). CT-SD solves steady-state shock and detonation waves in either normal or oblique incidence, and CT-ROCKET computes the theoretical performance of rocket engines under highly idealized conditions. Modules can be accessed through user-friendly GUI or from MATLAB’s command line in plain code mode.