A Collection of Fast, Exact and Eco-Friendly k-Means Clustering Algorithms R package geokmeans version 0.1.0 A collection of fast k-means clustering algorithms under a single, uniform interface. The core method is Geometric-k-means, a bound-free algorithm of Sharma et al. (2026) <doi:10.1007/s10994-025-06891-1> that uses geometry to restrict computation to the data points able to change clusters, substantially reducing distance computations and runtime while returning the same result as standard k-means. Also included are Lloyd's algorithm, Elkan, Hamerly, Annulus, Exponion, and Ball k-means. All algorithms are implemented in 'C++' via 'Rcpp' and 'RcppEigen' and return the final centroids, optional per-point cluster assignments, and computational statistics. Software Imports: Rcpp LinkingTo: Rcpp, RcppEigen Suggests: testthat (>= 3.0.0), knitr, rmarkdown Parichit Sharma <parishar@iu.edu> Comprehensive R Archive Network (CRAN) Parichit Sharma [aut, cre, cph], Hasan Kurban [aut] GPL-3 2026-06-22 application/tgz https://CRAN.R-project.org/package=geokmeans doi:10.32614/CRAN.package.geokmeans