How many gallons of water are there in the whole world?

Question

How many gallons of water are there in the whole world?

Answer 1

a lot

Answer 2

Trillions xD

Answer 3

1,370,000,000 km3

This amounts to 1,370,000,000,000,000 cubic meters

There are 227 gallons in a cubic meter therefore there are

310,000,000,000,000,000 gallons

That is 310 quadrillion give or take a few quadrillion

Oops, that is just the ocean so add about 10 more quadrillion

Answer 4

The earth is 70% covered by water and if you assume that the average ocean depth is about 8000 feet.  Add about 2% to account for fresh water and ice caps.  The surface area of the earth is defined by 4*pi*r*r.  

r is the radius or 1/2 of diameter which is the circumference/pi (3.14).  

72% of the surface area is 3,993,286,648,943,790 sq feet.

At an average depth of 8000 feet for the world's oceans the total gallons is area x depth X 7.481 gallons per cubic feet or:

238,990,219,365,988,000,000 gallons plus or minus a few billion.