Utility July 13, 2026 · 8 Min Read

Pool Volume Calculator – Guide & Formulas

Calculate the total liquid volume of rectangular, circular, oval, and freeform swimming pools in gallons and liters.

Determine the exact water capacity of your swimming pool. Choose from rectangular, circular, oval, or kidney-shaped pool layouts, enter the dimensions and depth profiles, and calculate total capacity in US gallons and liters.

Key Takeaway

Use the free Pool Volume Calculator to calculate the total liquid volume of rectangular, circular, oval, and freeform swimming pools in gallons and liters. Get instant results with step-by-step explanations.

How to Use the Pool Volume Calculator

  1. Select your pool geometric shape: Rectangular, Circular, Oval, or Freeform/Kidney.
  2. Enter the length, width, and depth profile (shallow end depth and deep end depth).
  3. For circular pools, specify the diameter and depth.
  4. Review your total calculated capacity in US Gallons, Liters, and Cubic Feet instantly.

The Formula

Average Depth = (Shallow End Depth + Deep End Depth) / 2 | Rectangular Gallons = Length * Width * Average Depth * 7.48 | Circular Gallons = Diameter * Diameter * Average Depth * 5.9 | Oval Gallons = Length * Width * Average Depth * 5.9 | Volume in Liters = Gallons * 3.78541

Variable Definitions

  • L: The length of the pool in feet
  • W: The width of the pool in feet
  • D_avg: The calculated average water depth in feet
  • 7.48: The constant converting cubic feet of water volume into US liquid gallons

Finding Capacity of an Inground Pool

Calculate the water capacity of a rectangular swimming pool that is 32 feet long, 16 feet wide, with a shallow end depth of 3 feet and a deep end depth of 8 feet.

  1. Step 1: Calculate the average water depth: (3 ft + 8 ft) / 2 = 5.5 feet average depth.
  2. Step 2: Calculate total pool cubic footage: 32 ft (Length) × 16 ft (Width) × 5.5 ft (Average Depth) = 2,816 cubic feet.
  3. Step 3: Convert cubic feet to US gallons: 2,816 cu ft × 7.48 gallons/cu ft = 21,063.68 US gallons.
  4. Step 4: Convert gallons to liters (optional): 21,063.68 × 3.78541 ≈ 79,735 Liters.

Frequently Asked Questions

Why is knowing my pool volume in gallons critical?

Knowing your pool capacity is the foundation for pool maintenance. All chemical treatments (chlorine dosage, algaecides, pH balancers) and pump sizing calculations require an accurate gallon capacity to avoid dangerous under-dosing or over-dosing.

How do I calculate volume for a freeform or kidney-shaped pool?

A standard approximation is to find the average width (add narrowest width to widest width and divide by 2) and use the oval formula, multiplying by a shape modifier of 0.85 to account for the inward curves.

Should I calculate volume to the pool coping or the water line?

Always calculate to the target water line (typically midway up the skimmer opening, which is about 4 to 6 inches below the top coping edge) to reflect the actual water weight and capacity.