Swimming Pool Volume, Gallons & Turnover Calculator

Pool Chemistry & Hydraulic Engineering: Volume Sizing

• The 7.48 Gallons per Cubic Foot Constant: 1 cubic foot of fresh water equals exactly 7.48052 US Gallons.

• The 8-Hour Turnover Rule: The Association of Pool & Spa Professionals (APSP) recommends filtering 100% of pool water volume at least once every 6 to 8 hours to prevent algae growth and circulate sanitizing chemicals.

How to Use This Calculator

Enter your Pool Geometry & Shape — choose from Rectangular / Square Pool (L × W × Avg Depth × 7.48), Circular / Round Pool (π × r² × Avg Depth × 7.48), Oval Pool (L × W × Avg Depth × 5.9), Pool Length or Diameter (Feet [ft]) (e.g. 32 (32 ft length or round diameter)), Pool Width (Feet [ft] - Not needed for round) (e.g. 16), Shallow End Water Depth (Feet [ft]) (e.g. 3.5 (3.5 ft shallow end)), Deep End Water Depth (Feet [ft]) (e.g. 8.0 (8.0 ft deep end)), and Daily Filter Pump Turnover Target (Hours) — choose from 6-Hour Fast Turnover (Heavy swimmer bather load), 8-Hour Standard Daily Turnover (Recommended), 10-Hour Energy-Saver Turnover (Variable speed pump). Results update instantly as you type — adjust any value to compare scenarios.

The Formula

Pool Hydraulics \& Volume equations:

Average Depth (ft) = (Shallow Depth + Deep Depth) / (2)

Rectangular Pool Volume (Gallons) = Length × Width × Average Depth × 7.4805

Circular Pool Volume (Gallons) = π × ((Diameter) / (2))^2 × Average Depth × 7.4805

Water Mass (lbs) = Gallons × 8.34 lbs/gal

Required Pump Flow Rate (GPM) = (Total Gallons) / (Turnover Hours × 60 Minutes)

Worked Example

For example, calculating the water volume of a 32' × 16' rectangular in-ground pool sloping from 3.5 ft shallow to 8.0 ft deep): Volume in cubic feet is . Total Water Capacity is \, weighing 91.8 Tons. Achieving an 8-hour daily turnover requires a filter pump flow rate of 46 GPM.

Understanding Your Result

Geometric calculations assume ideal shapes — real-world measurements should include a 5–15% tolerance for irregular shapes, cutting waste, and installation overlap. For construction applications: always verify calculated areas match your physical measurements before ordering materials. Standard practice is to measure the same dimension twice from different reference points and use the average. Express results in the units required by your supplier or building permit — conversions between cubic yards, cubic feet, and cubic meters must be precise for material orders.