Entry calculator · Sky and Earth · four pages
Fifteen Cubits Above the Mountains
Under the book's global-Flood premise, Mount Everest plus the stated clearance sets a minimum water surface. NOAA's global relief grid then distinguishes the additional water required from the total water present at peak.
Reference: Genesis 7:11–24 · Genesis 8:1–14
The passage names rain and the fountains of the deep but does not divide the water between them. This calculator therefore makes no rain-share assumption. It uses NOAA ETOPO 2022 terrain and bathymetry, not a flat Earth-area-times-depth slab.