Anybody have a formula to help calculate area into gallons?

Question

Hi all. I set up a little pool for my kids today. It's a round pool, 12-foot diameter by 3-foot deep. The chlorine instructs dosage by gallon, however.
What is the formula to calculate the size of the pool into gallons?
Much appreciated!

Answer 1

You asked to calculate area into gallons. Mathematicians are sticklers on the words for things, sorry! You meant to ask how to calculate VOLUME into gallons.

The volume of a pool is equal to the area of the base of the pool times the water depth.

The area of a circle is pi*r-squared. Pi is about 3.14, and the radius is simply half the diameter. For you, that's 6 feet. So,

area = (3.14)*(6)*( 6) = 113.04 square feet

since the water depth is 3 feet, the volume of your pool is

113.04 * 3 = 339.12 cubic feet

Now comes the tricky part. One cubic foot contains approximately 7.48 US gallons. In other words, there are 7.48 US gallons per cubic foot (see source).

So if each cubic foot has 7.48 gallons, multiply 7.48 by the number of cubic feet in your pool.

7.48 * 339.12 = 2537 gallons (rounded)

Answer 2

The area of the 12' pool is calculated using pi x radius^2, which in your case is

3.14 x 36 = 113.04ft^2

Assuming the total depth of the water is 3ft, rather than the height of the pool, then you multiply 113.04 by 3 to get the volume on cubic feet.

113.04 x 3 = 339.12ft^3

1ft^3 water = 7.48 gallons, therefore your pool holds
339.12 x 7.48 = 2536.6176 gallons

To make the measurements easier, work on 2537 gallons.

Complete formula would be

g = (3.14 x r^2) x 3 x 7.48
where g is the number of gallons in the pool, r is the radius of the pool (in feet) and d is the depth (also in feet).

Answer 3

Actually it's 2538.15 gallons (if you fill it TO THE TOP and 3 feet is the hight of the walls.)
If the walls are 3 feet tall, I assume you'd fill it to about 2.5 feet deep (you do not water to overflow, when kinds get into the pool right?)
So, if you have your 12 foot diameter pool filled to 2.5 feet deep, it will hold 2115.13 gallons of watter.

Answer 4

Area is 2-dimensional. Volume is 3-dimensional.

Square feet are UNITS for measuring area. Gallons are UNITS for measuring volume.

The volume of a cylinder with a 6-foot radius (r) and 3-foot height (h) is
V = pi*r^2*h
V = pi*(6 feet)^2*(3 feet)
V = 339.3 cubic feet
V = 2538 gallons

Answer 5

There are 7.48 gallons in each cubic foot. So, find the volume of the pool in cubic feet and then multiply by 7.48.
So,
6*6*3.14*3 = 339.12
339.12*7.48 = 2536.6176