Pool Volume Calculator
Calculate exact swimming pool water volume in Gallons and Liters for proper chemical balancing and filtration pump turnover rate sizing.
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How Pool Volume is Calculated
Calculating pool volume in US gallons requires computing the surface area in square feet, multiplying by the average water depth, and multiplying by 7.48 gallons per cubic foot:
Rectangular Pools
Gallons = Length × Width × Avg Depth × 7.48
Circular Pools
Gallons = π × Radius² × Avg Depth × 7.48
The Filtration Turnover Rule
Residential pool health codes recommend filtering the entire volume of pool water at least once every 8 hours. Sizing your circulation pump flow rate (GPM) is determined by: $$ ext{Pump GPM} = rac{ ext{Total Gallons}}{ ext{Turnover Hours} imes 60}$$
Frequently Asked Questions
Why is accurate pool volume critical for pool chemicals?
Every pool chemical (chlorine, muriatic acid for pH reduction, stabilizer/CYA, and algaecide) is dosed per 10,000 gallons. Overestimating volume causes chemical overdose, eye burning, and cloudiness; underestimating causes algae blooms.
How do you find average depth in a sloping pool?
For pools with a gradual slope from shallow to deep, average depth is simply: (Shallow Depth + Deep Depth) / 2. For hopper-bottom sport pools, account for the larger shallow shelf.
How much does pool water weigh?
Water weighs approximately 8.34 pounds per gallon (1 kg per liter). A 20,000-gallon in-ground swimming pool holds over 166,000 pounds (83 tons) of water.