How profound is the ocean's depth?

Understanding the ocean means grappling with some truly astonishing figures.

Around 71% of Earth's surface is covered by oceans. This vast expanse contains over 332,519,000 cubic miles — or 1,386,000,000 cubic kilometers — of water.

According to the official site of the U.S. National Oceanic and Atmospheric Administration, the ocean holds enough water to "fill about 352,670,000,000,000,000,000 gallon-sized milk containers!"

Let’s stretch our imagination and assume you don’t have that many empty milk jugs lying around. Here’s another wild visual: You could theoretically use the ocean to submerge the entire United States (yes, Alaska and Hawaii included) in a column of water over 82 miles (132 kilometers) high.

Excuse us for using a mild exclamation, but ... wow!

It’s no surprise that some of the most common questions about the ocean revolve around its depth. How deep is the ocean? Where's the deepest point? And what is the ocean’s average depth?

Today, you’ll discover the answers to these deep-sea questions, and as a bonus, you won’t even need to pack any scuba equipment.

The Average Depth of the Ocean

Technically, Earth has just one vast ocean. It’s a bit puzzling that this single body of water is divided into five distinct regions that are all called "oceans" in their own right: the Pacific Ocean, Atlantic Ocean, Indian Ocean, Arctic Ocean, and Southern Ocean.

Altogether, these regions form what is called the "global ocean." This is what people typically mean when they refer to "the ocean" in its entirety. (It’s also what we were talking about in the two earlier hypothetical examples.)

Naturally, the ocean’s depth isn’t consistent. It changes significantly depending on geography. In any given location on the map, the depth from the ocean's surface to the floor below could be affected by underwater canyons, mountain ranges, and other geological features.

Thanks to tools like sonar, radar, and satellite technology, scientists have determined that the global ocean’s average (mean) depth is around 12,785 feet (3,897 meters). That’s roughly 2.4 miles, or 3.8 kilometers deep.

The Deepest Parts of the Ocean

We can also examine various locations. A 2019 study published in Earth-Science Reviews analyzed available data to identify the deepest zones in each of the five subregions of the global ocean. Here’s what the researchers found:

"But hold on!" you might say. "What about the Pacific Ocean?" Don’t worry, we’ve saved the most fascinating part for last. To the east of the Mariana Islands, a chain of Pacific islands, there lies a vast underwater abyss that has captured the imaginations of adventurers and science fiction writers alike.

This mysterious abyss is called the Mariana Trench, and it harbors the deepest point not only in the Pacific Ocean but in the entire world’s oceans: "Challenger Deep." The trench is situated in the western Pacific Ocean.

Determining the exact depth of this trench is challenging, but a 2019 study offers a conservative estimate that places the ocean floor here at a staggering 35,843 feet (10,925 meters) beneath the surface.

So, how deep is Challenger Deep? Extremely deep. In fact, this Pacific spot is even deeper than the height of Mount Everest. The summit of that iconic Himalayan peak stands at about 29,026 feet (8,848 meters) above sea level. It’s the tectonic plate movements and interactions that create these extreme trenches, as well as the tallest mountains.