Mordred is a newly developed molecular descriptor calculation software that can calculate over 1800 two- and three-dimensional descriptors. It is freely available on GitHub and can be installed and used via the command line interface (CLI), web application, or as a Python package on major platforms (Windows, Linux, macOS). Mordred is designed to be easy to use, flexible, and highly efficient, with performance benchmark results showing it is at least twice as fast as PaDEL-Descriptor, a well-known descriptor calculator. Mordred can handle large molecules, which other software often cannot, and it includes automated tests to ensure accuracy. The software is licensed under the three-clause BSD license, allowing both commercial and non-commercial use. Key features include support for uncommon-range descriptors, product terms, and parallel computing. Mordred is a promising choice for cheminformatics studies, particularly in quantitative structure-property relationship (QSPR) research.Mordred is a newly developed molecular descriptor calculation software that can calculate over 1800 two- and three-dimensional descriptors. It is freely available on GitHub and can be installed and used via the command line interface (CLI), web application, or as a Python package on major platforms (Windows, Linux, macOS). Mordred is designed to be easy to use, flexible, and highly efficient, with performance benchmark results showing it is at least twice as fast as PaDEL-Descriptor, a well-known descriptor calculator. Mordred can handle large molecules, which other software often cannot, and it includes automated tests to ensure accuracy. The software is licensed under the three-clause BSD license, allowing both commercial and non-commercial use. Key features include support for uncommon-range descriptors, product terms, and parallel computing. Mordred is a promising choice for cheminformatics studies, particularly in quantitative structure-property relationship (QSPR) research.