Pool Gallon Calculator: Essential Tool for Pool Owners

Accurately determining the volume of your pool is crucial, whether you’re planning to install a new pool pump, heater, or need to add the appropriate amount of chemicals to your water. Hence, a pool gallon calculator becomes an invaluable tool for pool owners. This article provides a comprehensive guide on how to calculate your pool’s volume, both with and without a calculator.

At a Glance

  • Pool Volume Calculation: For a square or rectangular pool, multiply its length, width, and average depth, then multiply by 7.5 for volume in gallons. If the pool is circular, you need to use a slightly different formula: take the radius (half the diameter), square it (multiply it by itself), multiply by the depth and then multiply by 7.5 to get the volume in gallons.
  • Influence of Pool Volume on Equipment: Your pool’s volume impacts the size and capacity of equipment like pumps and heaters needed, but also more pool chemicals needed.
  • Energy Efficiency Considerations: A larger pool needs more energy to heat and circulate the water. Understanding your pool’s volume can help you choose the right equipment to optimize energy use. For instance, in the US, the average pool heater size is around 200,000 BTU for a 15,000-gallon pool.
  • Water Conservation Implications: Large pools demand more water, significant in water-scarce areas. Strategies like using pool covers to minimize evaporation help reduce water usage.

Why Do You Need to Know Your Pool’s Water Volume?

Knowing your pool’s volume is the first step to effective pool management. It allows you to determine the correct amount of chemicals needed to keep your pool safe and clean. Additionally, when considering the installation of a pool pump, heater, or any other pool equipment, knowing your pool’s water volume is essential as these devices come in different sizes based on the volume they can effectively service.

Pool Gallon Calculator

With this Pool Volume Calculator you can calculate, how many gallons your pool has.

Basic Pool Volume Calculation

Before diving into specific pool shapes and their volume calculations, let’s understand the basic formula for calculating pool volume:

Length x Width x Average Depth x Multiplier = Volume in US Gallons

The multiplier varies based on the shape of your pool. For rectangle, square, or free-form pools, the multiplier is 7.5. For round or oval pools, the multiplier is 5.9.

Pool Shapes and Their Volume Calculations

Different types of pools have different formulas for calculating volume. Let’s examine the most common pool shapes and how to calculate their volume.

Rectangular or Square Pools

Rectangular or square pools are the simplest to measure. If the pool has a constant depth, multiply the length by the width by the depth, and then by 7.5 to get the volume in gallons. Formula:

Length x Width x Depth x 7.5 = Volume (in gallons)

However, if your pool has variable depths with a gradual slope, you will need to calculate the average depth first. Add the shallow end depth to the deep end depth, and divide by two. Then, multiply the length, width, and average depth by 7.5 to calculate the volume of the pool in gallons.

Circular Pools

To calculate the volume of a circular pool, start by measuring the total diameter of the pool and divide it by two to get the radius. Then use the following formula:

3.14 (Pi) x radius^2 x depth x 7.5 = Volume (in gallons)

Oval Pools

For oval pools, the formula is a bit more complex:

Length x Width x (Pi/4) x Depth x 7.5 = Volume (in gallons)

Irregular Shaped or Kidney Shaped Pools

For irregularly shaped pools, the best approach is to break it down into multiple smaller, regularly shaped parts. Measure each part, calculate the volume, and then add them all together for the total volume.

Using a Pool Gallon Calculator

While manual calculations are helpful, using a pool gallon calculator can simplify the process. All you need to do is plug in your pool’s measurements, and it will automatically calculate the volume for you. This tool is particularly useful for irregularly shaped pools, saving you a lot of time and effort.

Common Pool Sizes and Their Volumes

Here is a quick reference chart for some common pool sizes and their approximate volumes:

Pool Size (in feet)Average Depth (in feet)Volume (in gallons)

When to Ask for Professional Help

If your pool has a particularly complex shape, or you’re having trouble with the calculations, don’t hesitate to call a professional. Pool professionals can accurately measure your pool and calculate its volume for you, ensuring you have the correct information for pool maintenance and equipment installation.

Effect of Pool Volume on Maintenance

The volume of your pool directly impacts the amount of maintenance it requires. Larger pools require more chemicals to maintain the ideal water balance. They also need larger pumps and heaters to function efficiently. Therefore, knowing how many gallons your pool holds can help you make more informed decisions about pool maintenance and equipment purchases.

The Role of Pool Volume in Energy Efficiency

Knowing your pool’s volume plays a crucial role in energy efficiency. Larger pools require more energy to heat and circulate the water. Therefore, the choice of equipment like heaters and pumps should align with your pool’s size to ensure efficient energy usage. Additionally, an understanding of your pool’s volume can help you leverage thermal layers or install a pool pump timer, allowing you to heat your pool efficiently without excessive energy use. Also, correct pool volume data allows you to optimally run your pump for an adequate time, saving energy while keeping your pool clean and clear.

Implications of Pool Volume on Water Conservation

Water conservation is an essential factor to consider when calculating your pool’s volume. A larger pool not only requires more water to fill, but also more water to maintain due to increased evaporation and backwashing the filters. For instance, pool covers can drastically reduce evaporation, and backwashing only when necessary can save significant water.


How Many Gallons is My Pool?

To calculate the volume of your pool in gallons, use the formula: length (ft) x width (ft) x depth (ft) x 7.5 for rectangular pools, and for circular pools use: radius (ft) x radius (ft) x depth (ft) x 3.14 x 7.5. Be sure to measure the average depth if it varies. Check our pool volume calculator.


Round Pool Volume Calculator

To calculate the volume of your round pool in gallons, use the formula: radius (ft) x radius (ft) x depth (ft) x 3.14 x 7.5. Be sure to measure the average depth if it varies. Or simply use our round pool volume calculator.


Water Volume Calculator

Calculate the Volume of Water with our pool gallon calculator, or use the following formula for rectangular volumes: length (ft) x width (ft) x depth (ft) x 7.5.


Calculate Pool Gallons

The volume of a rectangular pool in gallons can be calculated using the formula: length (ft) x width (ft) x depth (ft) x 7.5. For a circular pool, use the formula: radius (ft) x radius (ft) x depth (ft) x 3.14 x 7.5. Check our pool gallon calculator.