The Pacific Ocean is the largest of all the oceans and comprises about 48 percent of all ocean water. There are over 321 million cubic miles of water in all the oceans combined, according to the National Oceanic and Atmospheric Administration's National Geophysical Data Center.
The Pacific Ocean could contain all the world's continents and the vast majority of the oceans. In addition to being the largest ocean, the Pacific Ocean is also the deepest ocean. The average depth of the Pacific Ocean is over 12,000 feet, while the deepest point is 36,200 feet in the Mariana Trench. The Atlantic Ocean is 20 percent smaller than the Pacific Ocean.