The Flow Analysis Summary Statistics Tool for R, 'fasstr', provides various functions to clean and screen daily stream discharge data; calculate and visualize various summary statistics and metrics; and compute annual trending (using 'zyp' package methods < https://CRAN.R-project.org/package=zyp>) and volume frequency analyses (using methods similar to HEC-SSP (2019) < https://www.hec.usace.army.mil/software/hec-ssp/>). It features useful function arguments for filtering of and handling dates, customizing data and metrics, and the ability to pull daily data directly from the Water Survey of Canada hydrometric database (< https://collaboration.cmc.ec.gc.ca/cmc/hydrometrics/www/>).