Evapotranspiration Estimation Using Mass Transfer-Based Models R package ET0MassModels version 1.0.0 Provides functions to estimate daily reference evapotranspiration (ET0) using 10 mass transfer-based empirical models, with the Food and Agriculture Organization (FAO) Penman-Monteith method included as the standard reference for model comparison. Includes statistical evaluation metrics, such as Nash-Sutcliffe efficiency (NSE), root mean square error (RMSE), mean absolute error (MAE), and mean bias error (MBE), and visualization tools (scatter plots and Taylor diagrams). Based on Singh et al. (2026) <doi:10.1016/j.ejrh.2026.103925>. Software Depends: R (>= 3.5.0) Imports: graphics, grDevices, stats Suggests: testthat (>= 3.0.0), knitr, rmarkdown Samir Barman <samir.igfri@gmail.com> Comprehensive R Archive Network (CRAN) Ajay N. Satpute [aut], Samir Barman [aut, cre] (ORCID: <https://orcid.org/0000-0001-8181-8346>), Amit Kumar Singh [aut], Avijit Ghosh [aut], Gaurendra Gupta [aut] GPL (>= 3) 2026-10-21 application/tgz https://CRAN.R-project.org/package=ET0MassModels doi:10.32614/CRAN.package.ET0MassModels