This dataset provides elevation-area-capacity relationships for Lake Powell derived from a topobathymetric digital elevation model (TBDEM) that was collected in 2017 and 2018. The TBDEM was modified (Jones and Root, 2021, available for download at https://doi.org/10.5066/P9H60YCF) from the originally published version (Poppenga and others, 2020, available for download at https://doi.org/10.5066/P9XX0J1Y) for the purposes of this study. This dataset contains comma delimited (CSV) files for: (1) calculated tables of elevation-area-capacity relationships for Lake Powell at 0.33-ft (0.1-m) intervals; (2) interpolated tables of elevation-area-capacity relationships for Lake Powell at 0.01-ft intervals; and (3) an error analysis table conducted at 0.01-ft elevation increments across three elevation bands: lower (3,160.00–3,161.00 ft above NAVD 88), middle (3,400.00–3,401.00 ft above NAVD 88), and upper (3,700.00–3,711.00 ft above NAVD 88).