It is essential to know how many water gallons you have in your swimming pool for running it healthily and safely. It is crucial to see the swimming pool volume to make correct chemistry adjustments. If you want to know the proper chemical doses for your pool, you need to determine how many gallons of water it holds precisely.

Make sure you follow the manufacturer’s instructions before deciding to add chemicals to your swimming pool water. Yet, the instructions are valuable only if you know how many gallons of water your swimming pool holds. Plus, you also need to know how many gallons you are dealing with when adding a Solar Heater, Heat Pump, or Pool Heater to your pool.

Pool Measurement

Pool-Measurement How many gallons of water in a pool? (Answered)

One of the most important things to know how much your pool size is. To find out this, you have to know the pools’ width and length. Then, you need to evaluate the average depth of it. If you are the swimming pool owner, you should possess a drawing and documents to find the pool’s measurements.

If you are not the owner, you must estimate the pool volume by calculating and measuring dimensions. Based on water volume, you will be able to figure out the necessary amounts of shock, chlorine, and pH increaser, that you need to provide care for your swimming pool.

Chemical balance

Chemical-balance How many gallons of water in a pool? (Answered)

Chemicals overdosing can provoke harmful reactions among swimmers and damage equipment, so you must replace them more often. On the other hand, under-dosing can cause harmful pathogens to spread among swimmers, and again, there would be damaged equipment.

Measurement’s formulas and parameters

vol How many gallons of water in a pool? (Answered)

Distinct calculation parameters depend on the pool’s shape. More complex pool shapes need various calculations. The most commonly known pool shapes are:

  • Rectangle/ square
  • Oval
  • Circle
  • Oblong/ free form

Now, let’s take a closer look at calculating different volume shapes to determine your swimming pool amount of water.

Rectangle/ Square

Pool-Cabana-by-Orchard-Hills-Design-and-Construction-LLC How many gallons of water in a pool? (Answered)
Image source: Orchard Hills Design and Construction, LLC

The Length x width gives the pool’s surface result. When you multiply the number with the depth provides the result of the volume in cubic feet. In the end, bearing the pool’s cubic feet by 7.5 to have the result of gallons pool volume. It would be best if you keep in mind that in each cubic foot, there are 7.5 gallons.

Volume =Length x Width x Depth x 7.5

It is easy to calculate the volume of a standard rectangular pool. Yet, the calculation varies depending on the slope bottom pool. Under these circumstances, there are two types of depth such as deep depth and shallow depth. To specify the volume of the pool in this form, you need to determine the average depth of the swimming pool water and divide it by 2.

There is also a pool with a multi-rectangular form. When there are pools like these, you need to divide them into sections and calculate the volume of each section. When calculating, you will get the entire pool’s volume.

Circle Pools

New-Manor-Residence-by-Whitlock-Builders How many gallons of water in a pool? (Answered)Image source: Whitlock Builders

If you own a circular/round pool, then you should get the full pool’s diameter. Then, divide by 2 to get the pool’s radius. When you get the radius, use pi (π) to calculate the area. For those who do not know, the value of ‘π’ is 3.14. Plus, it would be best if you calculate the pool depth. Once you have all numbers, you can now calculate the volume of a round/circular pool. Here we provide you with the formula:

3.14 x radius2 x depth x 7.5 = volume (In gallons)

Oval Pools

Pools-by-Woodfield How many gallons of water in a pool? (Answered)Image source: Woodfield

To calculate the volume of oval pools, here you have the formula is:

Volume = length x width x π ÷ 4 x average depth x 7.5

Length x width x 3.14, divided by 4, x the average depth x 7.5 gives the volume in gallons. As the one with the rectangular pool, you can calculate average depth by adding the shallow and deep depths and later dividing by 2.

Oblong/ Freeform

Freeform-Cheleuitte-San-Antonio-by-Cody-Pools-Inc How many gallons of water in a pool? (Answered)Image source: Cody Pools, Inc

You will not only meet oval, round, rectangular, or square pools, but there are also classic kidney forms or some just wiggling all over the place. Freeform pools are pretty famous and exciting from a design perspective; they can be pretty tricky when calculating pool water volume.

If you are the owner of a free-form pool, you should contact the pool builder and ask for the pool volume that should be saved on the software he used. If the builder did not keep that information, then the only thing you can do is measure it.

To calculate a free-form pool, you need to imagine two or more regular shapes. When you try to see rectangles, circles, or other individual squares, it will be easier to calculate the volume. Then, try to measure them and use the previous calculations. Finally, add all together to discover the total volume.

As an example, we provide you with the following formula for a kidney-shaped pool:

Volume = length x (short width + the long width) x 0.45 x depth x 7.5 (in gallons) 

Extra Tips

If your swimming pool is round, you can measure it very easily the Diameter, Width, and Length only by using a tape measure/typical ruler. Plus, you will need one more person to help you because this tape is 35 feet long.


Calculator How many gallons of water in a pool? (Answered)

After you get all dimensions, use pool calculator apps to get the pool volume. The calculator of pool water is almost the same as the pool volume calculator. Why? Because it uses the same formulas from the square footage calculator. Furthermore, various applications include the Pool Volume Estimator in them.


chrt1 How many gallons of water in a pool? (Answered)

You will also find various available reference charts that include pools and their Average water gallons. These charts are great for people who do not care about the exact amount of gallons of water in the pool.

Keep in mind that the amounts and measurements cannot always be exact because it all depends on the size of the pool. By measuring pools by yourself, you will get experience and will always have better results. These reference charts are excellent for domestic uses.

Ending thoughts on how many gallons of water in a pool

Suppose your pool volume calculator or the pool volume chart does not work correctly because of your unusual pool shape. You are just tired of all the calculations; in that case, you should contact some pool professional who will take precise measurements and check the pool volume instead.

Pool professionals can also determine chemical proportion, heater size, and many more things that can be very useful to know. After you do all the measurements, your swimming pool is ready for the season. We wish you to have safe and happy swimming!

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