Pool Size Calculator
Use this calculator to determine the volume of your swimming pool in gallons and liters. Knowing your pool's volume is crucial for proper chemical dosing, heating, and pump sizing.
Understanding Pool Size
The size of your swimming pool, typically measured in gallons or liters, is a fundamental piece of information for any pool owner. It dictates nearly every aspect of pool maintenance and operation, from the amount of chemicals needed to the appropriate size of your pump, filter, and heater.
Why is Pool Volume Important?
- Chemical Dosing: Accurate chemical balancing (chlorine, pH, alkalinity, etc.) relies heavily on knowing your pool's exact volume. Over-dosing or under-dosing can lead to water quality issues, equipment damage, and health risks.
- Equipment Sizing: Pumps, filters, and heaters are rated for specific pool volumes. An undersized pump won't circulate water effectively, while an oversized heater will waste energy.
- Water Changes: When performing partial water changes or refilling your pool, knowing the volume helps you track how much water you're adding or removing.
- Cost Estimation: Understanding your pool's volume can help estimate costs for initial filling, heating, and ongoing chemical expenses.
How to Measure Your Pool's Dimensions
Before using the calculator, you'll need to accurately measure your pool. Always use feet for measurements when using this calculator.
For Rectangular Pools:
Measure the length, width, and average depth. If your pool has a shallow and deep end, calculate the average depth by adding the shallow depth and the deep depth, then dividing by two. For example, if the shallow end is 3 feet and the deep end is 8 feet, the average depth is (3 + 8) / 2 = 5.5 feet.
For Circular Pools:
Measure the diameter (the distance across the widest part of the circle, passing through the center). Then, measure the average depth as described for rectangular pools.
For Oval Pools:
Measure the longest length and the widest width of the pool. Then, measure the average depth. Our calculator uses an approximation for oval pools, which is generally accurate enough for most maintenance purposes.
Calculation Formulas Used
The calculator uses the following standard formulas to determine pool volume in cubic feet, which are then converted to gallons and liters:
- Rectangular Pool Volume:
Length × Width × Average Depth - Circular Pool Volume:
π × (Diameter / 2)² × Average Depth(where π ≈ 3.14159) - Oval Pool Volume (Approximation):
Length × Width × Average Depth × 0.89(The 0.89 factor approximates the area of an oval based on its overall length and width.)
Conversion Factors:
- 1 cubic foot ≈ 7.48052 US gallons
- 1 cubic foot ≈ 28.3168 liters
Example Calculations:
Example 1: Rectangular Pool
A rectangular pool is 25 feet long, 12 feet wide, and has an average depth of 5 feet.
Volume (cubic feet) = 25 ft × 12 ft × 5 ft = 1500 cubic feet
Volume (gallons) = 1500 cubic feet × 7.48052 gallons/cubic foot ≈ 11,221 gallons
Volume (liters) = 1500 cubic feet × 28.3168 liters/cubic foot ≈ 42,475 liters
Example 2: Circular Pool
A circular pool has a diameter of 18 feet and an average depth of 4.5 feet.
Radius = Diameter / 2 = 18 ft / 2 = 9 feet
Volume (cubic feet) = π × (9 ft)² × 4.5 ft ≈ 3.14159 × 81 sq ft × 4.5 ft ≈ 1145.11 cubic feet
Volume (gallons) = 1145.11 cubic feet × 7.48052 gallons/cubic foot ≈ 8,566 gallons
Volume (liters) = 1145.11 cubic feet × 28.3168 liters/cubic foot ≈ 32,430 liters