The NASA Lewis Research Center developed the CEA (Chemical Equilibrium with Applications) program to calculate chemical equilibrium compositions of complex mixtures and apply them to various problems. This report provides a user's manual and program description. The program requires two types of input: thermodynamic and thermal transport property data files (thermo.inp and trans.inp), and problem-specific datasets. The input datasets include reac (reactants), prob (problem type), outp (output options), and other datasets for specifying conditions and parameters. The program processes these inputs to calculate equilibrium compositions and output results in tables, including thermodynamic and thermal transport properties, rocket performance parameters, shock parameters, and detonation parameters. The program is modular, allowing modifications to the source code and data processing. It uses ANSI standard FORTRAN 77 and requires approximately 6300 lines of code with specific memory usage. The program's output includes input data, intermediate results, and final tables of results. The user manual describes the program's input and output formats, error messages, and examples of problem-solving. The program is designed to handle various types of problems, including combustion, rocket, shock, and detonation, and allows for the inclusion of ionized species and condensed phases. The program's data files are processed once and stored in binary libraries (thermo.lib and trans.lib) for future use. The program's output can be customized with options such as specifying units, printing intermediate information, and formatting data for plotting. The program is used to analyze chemical equilibrium and thermodynamic properties in a wide range of applications.The NASA Lewis Research Center developed the CEA (Chemical Equilibrium with Applications) program to calculate chemical equilibrium compositions of complex mixtures and apply them to various problems. This report provides a user's manual and program description. The program requires two types of input: thermodynamic and thermal transport property data files (thermo.inp and trans.inp), and problem-specific datasets. The input datasets include reac (reactants), prob (problem type), outp (output options), and other datasets for specifying conditions and parameters. The program processes these inputs to calculate equilibrium compositions and output results in tables, including thermodynamic and thermal transport properties, rocket performance parameters, shock parameters, and detonation parameters. The program is modular, allowing modifications to the source code and data processing. It uses ANSI standard FORTRAN 77 and requires approximately 6300 lines of code with specific memory usage. The program's output includes input data, intermediate results, and final tables of results. The user manual describes the program's input and output formats, error messages, and examples of problem-solving. The program is designed to handle various types of problems, including combustion, rocket, shock, and detonation, and allows for the inclusion of ionized species and condensed phases. The program's data files are processed once and stored in binary libraries (thermo.lib and trans.lib) for future use. The program's output can be customized with options such as specifying units, printing intermediate information, and formatting data for plotting. The program is used to analyze chemical equilibrium and thermodynamic properties in a wide range of applications.