How Many Gallons Of Water Are In The Ocean?

Earth’s oceans are one of the most mysterious parts of our planet.

How Many Gallons Of Water Are In The Ocean

No one really knows how far down the ocean really goes, and we have barely discovered the surface of what is down in the deepest parts of the earth’s oceans.

However, scientists have found a way to determine how deep the ocean is and how much water they contain.

In this article, we will be discovering how deep the ocean is, and how many gallons of water it is also made up of.

How Many Oceans Are There?

Globally, there is only one ocean, which is a vast body of water that covers approximately 71% of the Earth’s surface. Yet this one huge ocean is split geographically into particular regions.

The boundaries of these religions have changed over time, but they were split for various reasons.

IN the history books, we have always had 4 oceans including the Pacific, Atlantic, Indian and Arctic. Some countries, including America, recognize the Southern Antarctic as a 5th ocean.

Although, the most noted and well known ocean include the Indian, Atlantic and Pacific oceans.

How Much Water Is In The Ocean?

Scientists have been able to use special satellites to estimate the volume of water in the ocean. They discovered that the volume was 0.3 billion cubic miles. Yet this number was much lower than they thought it would be.

With this information, scientists then mapped the surface area and multiplied the volume by the average depth to work out a rough estimate of the amount of water that is in the ocean.

As a result, scientists believe that there could be either 343 million trillion or 343 quintillion gallons of water in our ocean.

Math Behind The Numbers

It is believed that there is around 1.3 billion cubic hm of water in the oceans. Then 1 km3 = 1 x 109 liters (1 x 109 is a trillion).

Hence, we can assume that there is roughly 1,300 trillion liters of water, which converts to 1.3 sextillion liters of water. However, we are looking for gallons here, so to convert that result into gallons, scientist had to do #the following.

3.78541178 liters are said to be in a gallon of liquid. Thus, 3.78541178 x 1.3 sextillion results in roughly 343,000,000,000,000,000,000 gallons. Therefore, it is estimated to be 343 quintillion gallons of water in the oceans.

Why Is The Volume Of The Ocean Decreasing?

Why Is The Volume Of The Ocean Decreasing

With each new reading of the estimate, the volume of water in the ocean is decreasing. However, this decrease doesn’t mean the ocean is losing any water.

Instead, researchers are discovering undersea formation like mountain ranges that take up more space, which would have taken up water.

Satellites have been able to show scientists that there are in fact much more mountains and bumpier ocean bottoms than we may have first thought.

When someone thinks of the bottom of the ocean, they may think it is smooth. Yet, we are discovering that this isn’t the case at all.

Measuring The Ocean Using Satellites

Obviously, satellites don’t measure the actual bottom of the ocean. Instead, satellites will measure the surface of the ocean to discover what is underneath it.

For example, if there is a mountain range under a particular part of the ocean, the satellite will pick it up, and you will notice the surface of the ocean will slightly bulge out.

Scientists have said that the satellites that are monitoring and calculating the depth of the ocean have all the oceans coveted.

The only one that caused any issues was the Arctic Ocean, as some areas are always covered in ice. Therefore, it is difficult to see what is underneath and the ice is blocking the satellite’s view.

With that being said, the satellites aren’t always accurate due to their spatial resolution.

So when mountains appear on the satellites, they appear as quite blurred in images. This is because the resolution on these satellites are 15 times lower than Moon and Mars maps.

As a result, ship based measures are required to gain and fine tune the data that is delivered by the satellites. Yet, ship based measurements like sonars have only mapped 10% of the overall ocean floor.

It has been estimated that it would take one ship around 200 years to map the whole ocean floor using nothing but echo sounders.

Surface Water Vs Groundwater In Earth

The earth is made up of a lot of water. The surface of the Earth is made from around 71% water, with 96.5% of the water being found in the ocean. There Is also water vapor in the air, groundwater in soil and water in lakes and rivers to think about as well.

A lot of the water that you see running into rivers comes from groundwater. Rainwater drains into the ground, which then finds its way to rivers and lakes etc. Humans are known to use both surface and groundwater.

Groundwater is really important as it is used for drinking purposes and keeps crops healthy and alive. While surface water helps to keep rivers and lakes as full as possible.

In 2010, it was calculated that America used around 275 billion gallons of surface water every day and 79.9 million gallons of groundwater every day.


A lot of water makes up Earth, with a majority of the surface water being found in the ocean.

It has taken us a long time to find out the depth of the ocean, as no one really knows how deep it is. Still today, scientists are finding new areas of the ocean floor that they didn’t know existed before.

It is roughly estimated that there are 343 quintillion gallons of water in the ocean. However, as scientists do more research, this figure could always change.

Mike Noren