How to Calculate Swimming Pool Volume in Gallons
Not many people know the value of swimming pool measurements in its care and maintenance. You might be wondering why you need to know the number of gallons of water in your pool.
This information is essential because it determines the number of chemicals needed in the pool, the ideal heater size to use, and much more. For instance, if your pool holds more water, it is only logical that the amount of chemicals increases correspondingly to ensure that it remains clean and suitable for swimming.
The ideal tool to use in calculating your pool volume is a calculator. Following manufacturer instructions in adding chemicals only becomes effective when you know the number of gallons in your pool.
Furthermore, if you seek to make the most out of your pool, measuring its volume should be considered a necessary routine. We will be highlighting the different ways to calculate your pool volumes and everything you need to know on volume calculation in gallons. Find out more.
Calculations on Pool Volume
The following indices determine the volume of your pool:
- Shape (Rectangular or round)
- Length
- Width
- Shallow end
- Deep end
The measurements below are the surface area calculations for regular pools:
Area of a Square or Rectangle: A = L × W
Area of a Right Triangle: A = (L × W) ÷ 2
Area of a Circle: A = Pi × r2
Multiplying the length and breadth (Width) gives you the pool’s surface area and introduces the depth gives you the overall volume. However, it is much more than that. Your pool’s volume also depends on the slope at the pool bottom. For instance, a constant pool depth at the bottom gives you a single figure to multiply by the surface area and then by 7.5 (because 1 cubic foot of water contains 7.5 gallons) to get your volume in gallons. In other words, the volume of a pool with uniform depth is:
Length x Width x Depth x 7.5 = Volume (In Gallons)
Thus, if you have a pool that is 40 feet long, 20 feet wide, and 6 feet deep, the number of gallons would be:
40 x 20 x 6 x 7.5 = 36,000 gallons. Hence, 36,000 gallons would be needed to fill that particular pool.
Pools with Variable Depths
Only a few pools have uniform depths. Most pools have shallow and deeper ends. Therefore, another formula is needed to determine the volume of such pools. Calculating the average depth of a pool with variable depths allows you to get the required depth. To carry out this calculation, simply add the shallow and deep end depths and divide them by 2. That is to say:
(Shallow depth + deep depth) / 2 = Average depth
For instance, a pool might have its shallow side at a depth of 5 feet and the deep side at 11 feet. The average depth would be (5 + 11)/2 = 8 feet. Afterward, you can calculate the volume as in the example above but with the average depth in place this time. Thus, the formula becomes:
Length × Width × Average depth × 7.5 = Volume (in gallons)
N.B: Please note that this formula only works for variable depth pools with gradual slopes. Pools with steeper slopes cannot be calculated through this method.
Variable depth pool with a drop-off means that there is a sharp drop or demarcation in depth between the shallow end and the deep end. For such pools, calculating the average depth is different. For instance, if the shallow end is 5 feet and the deep end is 11 feet, they should be treated as separate pools, have their volume calculated independently, and summed up to get the pool’s total volume.
Other Special Cases in Pool Measurements
Round volume pool
To calculate the volume, measure the pool’s diameter and divide it by 2 to get the radius. Afterward, proceed with the formula below.
3.14 × radius2 × depth × 7.5 = volume (gallons)
Your pool’s diameter is measured at the widest part of the pool. Dividing it by 2 gives you the radius of the pool. For instance, if a pool’s diameter is 40 feet, the radius would be 40/2 = 20. Assuming the pool has a depth of 6 feet, the volume would be:
3.14(Pi) x 202 x 6 x 7.5 = 56,520 gallons
Freeform pools
This category refers to pools without any defined shape. They might also be termed irregular pools. They have rapidly become popular because of the aesthetics they provide. However, calculating their volume is more complicated than it seems.
First, you have to break down the pool into smaller bits of regular dimensions. For example, a bean-shaped pool can easily be divided into two circles. Subsequently, you would then get the volume of each circle and add them up for the pool’s total volume.
Freeform pools usually have uneven measurements, and dimensions might end up not being round numbers. It is best to round off each measurement to the nearest foot or decimal point for simplicity of calculation in such cases. This calculation method is not as accurate as other methods and has often been described as “winging it.” Nevertheless, a professional would give you near-accurate results for such pools.
Importance of Swimming Pool Volume Calculations
Different substances are added to pools to make them swimmable. These include chlorine, shock, pH increaser, and other pool care chemicals. Thus, understanding how to calculate your pool volume means your pool will become clear and ready for the season. Nothing sucks more than not being able to stay underwater as you would have desired because of the pool’s poor distribution of chemicals.
You no longer need to deal with adding too much chlorine, skin irritation, or not having enough shock. You can also save more money that would have gone into the purchase of materials, repairs, and installations by managing your pool calculations better. Pool volume calculations ensure that your pool is more durable and that the materials last longer.
Hire a Pool Professional Today
Volume calculations for pools could be tiring and time-consuming for inexperienced people who are not into math. Therefore, it is best to consider hiring a pool professional to do the work for you. Moreover, many modern pools no longer follow the classic rectangular, round, or square shapes.
Some might be oval, kidney-shape, or ill-defined, making it harder for you to get their volumes. In such instances, you do not just have to deal with the math alone but with the hassles of properly caring for your pool. Hence, the value of a pool professional cannot be overemphasized.
Pool calculators and volume charts are great but best handled by experts. Besides, they are not as accurate as professionals. Furthermore, they do not replace the need for an expert who has been in the industry for decades.
Pool experts understand the importance of volume calculations in gallons and can guarantee better results for you. In the end, it is a wise decision and investment to know your pool capacity. So this is all you may need to learn about calculating swimming pool volume in gallons. Enjoy your swimming!
