The average depth of the ocean is approximately 3,682 meters (about 3.7 kilometers or 12,080 feet). This estimate is based on satellite measurements and research conducted by NOAA and other oceanographic institutions. While the ocean floor is not flat and varies widely in depth, this figure represents the overall average depth across the world's oceans. The deepest known part of the ocean is the Challenger Deep in the Mariana Trench, which reaches about 11 kilometers deep. So, the average depth of the ocean is around 3.7 kilometers.