Pond Volume Calculator: How Big Is My Pond?

Our pond volume calculator makes math easy as 1-2-3

A pond in a landscaped garden
Photo: cjmckendry / E+ / Getty Images
A pond in a landscaped garden
Photo: cjmckendry / E+ / Getty Images
Amy Freeman
Written by Amy Freeman
Contributing Writer
Updated Jun 1, 2025
Highlights

  • Knowing how much water your pond can hold allows you to properly maintain it.

  • You can calculate pond volume by multiplying the pond's area by its depth. 

  • The exact formula you use depends on whether you're measuring in gallons or liters.

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You may be looking out at your yard and asking yourself, "How big is my pond?" When calculating the size of your pond, you first need to measure its area, then find the volume to determine how much water it can hold. The water volume of the pond will determine the amount of treatment product to use and how many fish can call it home.

How Much Water Is Needed for My Pond?

To find out how many gallons of water your pond needs, multiply its volume by 7.48, which is the number of gallons in a cubic foot. If you're using liters, multiply the volume by 1,000, the number of liters in a cubic meter.

Pond Volume (Cubic Feet)Water Needed (Gallons)Pond Volume (Cubic Meters)Water Needed (Liters)
3627011,000
7253922,000
1441,07833,000
3242,42444,000
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How to Calculate Pond Volume

You need three measurements to calculate the volume of your pond: its length, width, and depth. 

Pond Volume = Length x Width x Depth

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How to Measure Your Pond

For a pond that's rectangular or square in shape, you simply need to measure the length and width to find the square footage. From there, multiply the square footage by the pond's maximum depth to get the overall volume. 

For circular or irregularly shaped ponds, you need to use a slightly different formula. 

How to Measure a Circular Pond

To measure a circular pond, you'll need to find out the area of a circle. The formula for that is πr squared, or 3.14 times the circle's radius squared. 

Measure the pond's diameter, then divide that by two to get the radius. For example, if your pond has a diameter of 8 feet, the radius is 4 feet. The total area is 3.14 x (4 squared), or 50.24 feet.

Multiply that by the maximum depth to get the volume of the pond.

How to Measure an Irregularly Shaped Pond

If your pond has an irregular shape, such as a kidney bean or oval shape, the best way to measure is by creating straight lines around the perimeter of the pond, then measuring the length and width of those lines. 

Multiply the length and width to get an approximation of the pond's square footage. Then, multiply that by the maximum depth to get the volume of the pond.

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Who to Hire to Create a Pond

A man cleaning a pond
Photo: suravikin / iStock / Getty Images Plus / Getty Images

Who should you hire to create a pond? Your best bet is to work with a local pond builder, who can help you determine the right size for your property, as well as the optimal shape for your needs. 

If you're hoping to stock the pond with aquatic life, such as koi or other types of fish, a professional pond builder can also provide guidance on the best species to choose and how many fish to stock in the pond.

Frequently Asked Questions

How many fish can call your pond home depends on the volume of the pond and the fish size. Your pond's filtration system also influences the number of fish that will thrive in a pond. A general rule of thumb is to have 1 inch of fish for every square foot in a pond that's 2 feet deep. Another rule of thumb you can follow is to have one koi fish for every 200 gallons of water or two goldfish for every 200 gallons.

The average pond maintenance cost is $2,000. But how much you pay to take care of your pond depends on multiple factors, such as the size of the pond and whether fish live in it. Your area's climate also affects the overall maintenance cost, as you may need to winterize your pond to protect it and any aquatic life in it during the colder months.

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Learn more about our contributor
Amy Freeman
Written by Amy Freeman
Contributing Writer
Amy is a content writer specializing in home improvement and personal finance topics. She loves helping people tackle DIY projects that beautify their spaces. Her work can also be found on Money Crashers and Coldwell Banker where she combines home improvement and money saving tips.

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