This tutorial introduces statistical power analysis in R using the pwr package, covering sample size determination, power calculations for common statistical tests, effect size estimation, and post-hoc power analysis. It is aimed at researchers in linguistics and the humanities who want to design adequately powered studies or evaluate the statistical sensitivity of completed research. This tutorial is part of the Language Technology and Data Analysis Laboratory (LADAL), a free, open-access research infrastructure at the University of Queensland. LADAL provides tutorials, tools, and courses for researchers working with language data. All materials are freely available at https://ladal.edu.au and are part of the Language Data Commons of Australia (LDaCA), funded by ARDC and NCRIS.