Pond Calculator

pond volume calculator is a very helpful widget to keep available by your side when building a pond. It allows for you to determine what may be required in order to maintain the pond or water garden you have in mind. 

This free pond volume calculator can be used to calculate how many gallons of water your pond contains! 

koi fish in depth of water

Please keep in mind, the pond volume and (therefore pond volume calculator accuracy) shape plays a vital role (especially depth values) in pond volume calculators and we are providing rough estimates for a circular pond. Any hesitations about progressing in your project then contact the product garden supply providers where you placed your orders directly. Now - let's dive into the depth of this!

The Simple Pond Calculator:



How many gallons is my pond volume?

pond volume in gallons

Similar pond volume calculations for pond size can be done to obtain liner size, pump size, the type of pond pump recommended, and more. A pond pump calculator takes into account the pond length, width, surface area, and maximum depth for pond dimensions.

calculate pond volume

Here's an example of a pond volume calculation:

Assuming the pond volume dimensions averages are 8 feet by 4 feet and averages 2 feet deep. Multiply average length (feet) x average width (feet) x average water depth (feet) x 7.48 gallons per cubic foot.

per hour calculation help

Different Pump Size & Liner Size For Your Fish Pond

Pump Size and Pond Volume Correlation:

Pond pumps are sized by gallons per hour (GPH) at one foot of lift or height. Larger capacity pump size is rated by horsepower. To determine the size pond pump, we need to calculate the volume of water in the pond.

Dimensions are specific: To calculate the pond volume of water in gallons, simply multiply the:

Length in feet x width in feet x average depth in feet x 7.5

liner size help with values

Pump Sizing in varying pond volumes:

Performance charts included on the pond pumps are very useful and will take into account gallons per hour (GPH) as well as the head rating the pond requires. You'll notice that each chart displays changes in pressure and performance of a pump in different heights. The water gallons per hour are specific for pond pumps on purpose and the last thing you want is to have a disastrous koi fish and liner mishap!

Different Voltages And Applications:

A 120-volt pump can be very useful for circulating water within a pond as well as powering a small water feature. Think, small fountain here. The 220-volt pump is great for larger-scaled water circulation loads and for powering a large water feature. Think, waterfall features here.

understanding pump voltages

You may notice a common theme at this stage. Check for the manufacturer's performance chart supplied with potential pumps to find a pump capable of supplying the GPH you require at your desired lift for your waterfall feature.

Pond Liner Size Calculators:

The size of pond liner required can be calculated in the following way:

Maximum length in feet+ (2 x maximum depth of pond in feet) x maximum width in feet + (2 x maximum depth in feet). Here, the overlay is added into the length and width pond measurements. 

Or, take each measurement and use our pond liner calculator to do the calculation for you! It's simple to use and since liner size can be tricky to nail down, leave the number crunching surface area for your fish pond to us.

pond calculator accuracy and electric shock warning

Not all pond number crunchers are created equal however and please confer with professional builders if you are unsure of any values.


Always make sure the submersible pump items are unplugged during installation or when making adjustments. Picking up a live pump with wet hands or when standing in water or on wet surfaces can cause a fatal electrical shock.

Pond Calculator Use and Conclusion:

It's fun to calculate how many gallons your new water venture will require but it is vital to stick to the specifications of each individual tool. Contact a professional or the company of the tool directly if you have any hesitations or doubts. These items are not to be taken lightly!