Home » Rectangle Pool Volume Calculator With Volume Chart 

Rectangle Pool Volume Calculator With Volume Chart 

Trying to calculate the volume of your rectangular pool? In this post, I you can use the calculator to calculate how many gallons or litres are in your rectangular shaped swimming pool. Or if you’re included, you can do the math (I’ve broken it down below).

Rectangle Pool Volume Calculator (Gallons or Litres)

Rectangle Pool Volume Calculator

To calculate how much water is in your rectangular pool:

Step 1) Select the units: litres or gallons
Step 2 ) Enter your pool’s measurements in meters or feet

About the Rectangle Pool Volume Calculator

I designed the rectangle pool volume calculator to be as easy to use for calculating your angular pool’s volume as can be. You can toggle between litres or gallons without having to do any cross-calculations. I took care of all those for you.

You only need to know your rectangular pool’s average depth (for the shallow and deep ends) and width and length. Input the numbers, and the calculator does everything else for you.

I’ve also compiled pool volume charts you can refer to and formulas for doing the calculations yourself if you’d like to challenge my pool volume calculator or be doubly sure you got the numbers correct.

Rectangle Pool Volume Charts

Do you need to know the volume of your swimming pool fast and don’t have time to use the calculator? Or perhaps you’re looking for a frame of reference to check your work against? That’s what this rectangle pool volume chart is for.

Search for your pool’s width and length on the volume table, and then use the recommended volume as a benchmark when adding water. However, these are only approximate values.

12 ft x 24 ft (3.7 m x 7.3 m)10,800 gallons (40,882 litres)
16 ft x 32 ft (4.9 m x 9.6 m)19,200 gallons (72,680 litres)
16 ft x 36 ft (4.9 m x 11 m)21,600 gallons (81,765 litres)
18 ft x 36 ft (5.5 m x 11 m)24,300 gallons (91,986 litres)
20 ft x 40 ft (6.1 x 12 m)30,000 gallons (113,562 litres)
Use this chart for a quick reference for your rectangle shape pool volume (litres or gallons).

Measurements to Work Out Rectangle Pool Capacity

rectangle pool measurement

Calculating the capacity of your rectangular pool isn’t too difficult. You only need four measurements.

  1. Length
  2. Width
  3. Shallow End Depth
  4. Deep End Depth

If your pool has a constant depth, then just use the one depth.


rectangle pool measurement
How to measure the length and width of a rectangle pool

The length of your pool is how long it is lengthwise from the shallow end to the deep end. Just take a tape measure and measure from one end to the other. Standard lengths for a rectangular pool are 24, 32, 36, and 40 feet, as the chart above illustrates. 


The width of your rectangular pool is how far across it is from one horizontal side to another. The standard widths for a pool of this shape are 12, 16, 18, or 20 feet. But this does vary.


rectangle pool measurement
How to measure the depth of a rectangle pool

Round pools have a constant depth, which means they have one average depth across the entire length of the pool. It’s different for rectangular pools, which often have a sloping bottom resulting in a deep and shallow end.

The best way to deal with this is to take the average of the deep and shallow end. To do this, take a tape measure and measure to the bottom of the pool to the top at the deep end (D2 as shown on the diagram) and the shallow end (D1). To get the average, add the two numbers together and divide by 2.

How Do I Calculate the Volume of a Rectangle Pool?

We already went over two methods for determining the gallonage of a rectangular-shaped swimming pool: using our pool volume calculator or the volume chart above.

I want to share the formula for calculating rectangle pool volume for the old-school among us who enjoy doing math in our heads (or on paper!).

Formula to Calculate Rectangular Pool Volume

Here’s the formula to find your rectangle shape pool’s capacity:

V = L x W x D

V = Volume
L = Length
W = Width
D = Average Depth

Rectangular Pool Volume Calculations in Gallons

To use the above formula for calculating your rectangle shape pool volume in gallons, you’ll simply substitute your pool’s length and width (both in feet) for the letters in the formula.

For the average depth, take the shallow end depth measurement and add it to the deep end depth. Divide the result by two to get the average. e.g. If the shallow end is 3 feet and the deep end is 5 feet, 3 + 5 = 8. Divide 8 by 2 to arrive at an average depth of 4 feet.

e.g. let’s say your pool had a length of 24 ft and width of 12 ft and the average depth of 4 ft as calculated above, then the formula would look like this:

V = 24 x 12 x 4
= 1152 cubic feet

The next step is converting your answer to gallons.

Convert Cubic Feet to Gallons

To convert the volume in cubic feet to gallons, multiply it be the conversion factor of 7.48.

Volume (gallons) = 1152 cubic feet x 7.48
= 8,617 gallons

Calculating a Rectangle Pool Volume in Litres

Let’s discuss how to measure the volume of your rectangular pool in litres instead of gallons. You must first determine the cubic meters. That requires you to multiply the pool’s surface area (width x length) by its average depth.

e.g. your rectangle shape pool has an average depth of of 1.6 meters and a length of 9 m with a width or 5 m, then the formula would look like this:

V = 9 x 5 x 1.6
= 72 cubic meters

Converting Cubic Meters to Litres

Now you’re ready to take those cubic meters and convert them into litres. It’s a simple conversion, as 1 cubic meter is 1,000 litre, we simplify multiply the cubic volume by 1000. It looks like this:

Volume (litres) = 72 cubic meters x 1000
= 72,000 litres

What Can You Use the Rectangle Pool Volume Calculator For?

You have three methods for working out the volume of a rectangular pool, although the calculator remains my favorite. Now that you have this information, what can you do with it?

I’m glad you asked. Here are several situations where it pays to know how much water goes into your rectangle swimming pool.

1. Adding Chemicals and Treatments

A healthy swimming pool requires plenty of chemicals, but you must tread carefully. Using too much of a chemical will cause your water to be out of balance. Use the calculator to work out the water capacity of your pool. From there you can figure out how much of each chemical you need.

2. Purchasing Pool Equipment

Knowing the water capacity of your rectangular shaped pool is essential when purchasing pool equipment.

The right filter and pump for your swimming pool can handle the water at the volume it’s designed to be filled. Pool equipment that’s too powerful can strain the other components of your pool, such as the plumbing.

However, when the filter and pump are too weak, you won’t have enough water turnover. Which more than likely will mean the water will be cloudy.

3. Filling the Pool

The last benefit of the rectangle pool volume calculator is to determine precisely how much water to add to your pool. This is especially handy if you need to have water delivered to fill your pool.

What Is the Standard Depth of a Rectangle Pool?

The standard depth of a rectangular pool varies depending on the pool size. For example, a 16 by 32-foot pool will have a deep end of eight feet, but a 16 by 40-foot pool would have a 16-foot shallow end.

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