Having a pool at home is one of life’s pleasures. You can have a great time in the hot months without having to hit a general swimming pool. However, if you have a pool, you need to maintain it to get the best from it. Maintenance includes sanitizing your pool water and balancing the pH level. To do these correctly, you need to know how to figure the volume of a pool.
In this post, we consider some of the valuable formulas and tips that can help calculate pool volume and know the volume of around the pool.
Calculating Pool Volume
One of the vital things that every pool owner must know, like the back of their hand, is the measurement of their pool. The dimensions and volume of the pool water are critical. This is because all the calculations you make, ranging from the number of chemicals to apply to the pumps that you buy, and even the filters you purchase, are dependent on the water volume of your pool.
If you didn’t already know the volume, do not fret. We have provided tips that will help you to get the correct volume.
Before you calculate volume, there are some basic measurements that you must have handy. These include:
- Pi (3.14)
Calculating Volume of a Round Pool
Pools come in various shapes, and this section will focus on how you can get the water volume of a round or circular pool.
The basic formula you should keep in mind is Pi x Radius Squared x Average Depth x 7.5. The result of this multiplication provides the volume in gallons.
Pi is 3.14 and is a constant. The radius is half of the diameter. To get the radius of the pool, measure the distance from the broadest part of the pool and divide it in half to get the radius. ‘Radius Squared’ means that the radius is multiplied by itself. For example, if the measured radius is 4 feet, the radius squared is 4 x 4, which equals 16.
Let’s use a practical example.
If, for example, your pool is 12 feet in diameter. The radius will therefore be divided by 2.
12/2 = 6
To square the radius, you will multiply the radius twice.
R x R = R Squared.
So for the 12 feet diameter pool with a 6 feet radius
6 x 6 = 36
The next thing is to measure the depth of your pool. Let’s say that it is 8 feet deep. We will use the formula stated earlier (Pi x Radius Squared x Average Depth x 7.5).
So, the pool’s volume is:
3.14 x 36 x 8 x 7.5 = 6782.4 gallons.
Calculating for an Oval Pool
For this type of pool shape, you will use the formula:
(Length x width x Pi) / (4 x Depth x 28.31). Note that this is in litres and not gallons.
To convert to gallons, simply multiply the result by 0.264172.
You can take all these measurements and calculate it yourself. Or you could use an online pool gallon calculator oval.
It’s pretty easy and straightforward, isn’t it?
But what if your pool isn’t circular? The next section shows how you can get the number of gallons for a rectangular or square swimming pool.
How to Calculate the Volume of a Rectangular or Square Swimming Pool
Here is how you can correctly calculate the depth of your square or rectangular pool.
With Regular Depth
If the pool has a regular depth all through its length, then your calculations are pretty straightforward. You simply need to measure the length and width to know the surface area of the pool. The surface area’s value is then multiplied by the depth to know the volume in cubic feet.
To convert to gallons, then you will multiply the figure by 7.5. The entire equation is laid out below:
Length x Width x Depth x 7.5 = Volume in gallons
If the pool is 12 feet in length, 8 feet in width, and 2 feet deep, your volume will be as follows:
12 x 8 x 2 x 7.5 = 1440 gallons.
Pool with Variable Depth
Some pools come with varying depths and even have a gradual slope. If this is the case with your pool, you will need to do more calculations.
The first step is to know the average depth of the pool. How can you calculate this? By adding the two variable depths, then dividing the result by 2.
(Shallow Depth + Deep Depth)/2 = Average Depth.
If the one end is 2 feet and the other deeper end is 10 feet, the average depth would be
(2 + 10)/2 = 6 feet.
The next step is to find the surface area of the pool. Then multiply the result by the average depth. For example, if you have a 40 feet long pool with 14 feet width and 6 feet average depth, the volume would be as follows:
40 x 14 x 6 x 7.5 = 25200 gallons.
What if your pool doesn’t have regular shapes, as is common in many kiddie pools? Here is how to calculate uneven kiddie pool gallons.
If the pool in question is irregularly shaped, you can calculate the volume by breaking the pool down into smaller, regularly shaped segments.
These might be circles, squares or rectangles. Use the appropriate formula for each segment and add your results to get the total volume in gallons.
This article is a great resource that can help you to calculate the capacity of your pool. When measuring, remember that you should measure from the water’s depth instead of the wall’s height. The calculation you do would depend on the pool shape.
By calculating your pool’s gallons, you can know the maximum capacity of people it can take, the number of chemicals you should use, and other vital information about your pool.
If the math is too stressful for you, you can use an online pool gallon calculator oval or some other shape to get accurate values.