A C++ package designed for the convenient general-purpose analysis within a family of hadron resonance gas (HRG) models. **Reference**: [Comput. Phys. Commun. **244**, 295 (2019)](https://arxiv.org/abs/arXiv:1901.05249) [ Source code](https://github.com/vlvovch/Thermal-FIST) [ Online documentation](https://fias.uni-frankfurt.de/~vovchenko/project/thermal-fist/doc/)