Pool Calculator

Estimate how many gallons of water a rectangular pool holds — useful for dosing chemicals, sizing pumps and filling time.

How the Math Works

The Pool Calculator uses a straightforward geometric formula to determine water volume. First, it calculates the pool's volume in cubic feet by multiplying its length, width, and average depth. Since pools often have sloped bottoms, the average depth is typically calculated as (shallow end depth + deep end depth) / 2. To convert cubic feet to gallons, the result is multiplied by 7.48052, the number of gallons in one cubic foot. This ensures precise measurement for maintenance and chemical balancing.

Practical Applications

To use this calculator, measure your pool's length and width in feet, and determine the average depth by averaging the shallow and deep ends. Input these values into the formula or calculator tool. For irregular shapes, divide the pool into sections, calculate each section's volume, and sum them. This method is essential for accurately estimating water capacity, which is critical for tasks like adding chemicals, heating, or refilling after maintenance.

Day-to-Day Use

Knowing your pool's exact volume helps you manage daily operations efficiently. It ensures you add the correct amount of chemicals to maintain water quality, avoiding over- or under-chlorination. You can also estimate heating costs by calculating how much energy is needed to warm the water. Additionally, understanding the volume prevents overfilling, saving water and money. Whether you're a DIY pool owner or hiring a service, this calculation simplifies maintenance planning and resource management.

Worked example

32×16 ft pool, 5 ft average depth → 2,560 ft³ × 7.48052 = 19,150 gallons.

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