Engineering

Pool Calculator | Volume, Chlorine, pH & Chemical Dosing

Calculate swimming pool water volume in gallons for any pool shape — rectangular, oval, round, kidney, and L-shaped. Uses volume to calculate correct chlorine, shock, alkalinity adjustment, stabilizer, and pH balancing chemical doses with turnover rate and pump run time.

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Pool Shape

Length (ft)

Width (ft)

Depth Type

Shallow End (ft)

Deep End (ft)

Chemical System

Pool Volume Formula

Pool volume in gallons is calculated by multiplying surface area (in square feet) by average depth (in feet), then by 7.48 gallons per cubic foot. For pools with variable depth, use the average of shallow and deep end depths. Irregular shapes like kidney pools use a shape factor (approximately 0.82) to account for the curved areas.

Ideal Water Chemistry Targets

Parameter	Ideal Range	Effect if Off
pH	7.2–7.6	Low: corrosive. High: chlorine ineffective.
Free Chlorine	1–3 ppm	Low: algae/bacteria. High: skin irritation.
Total Alkalinity	80–120 ppm	Stabilizes pH from swinging.
Calcium Hardness	200–400 ppm	Low: etches plaster. High: cloudy water, scaling.
Cyanuric Acid (CYA)	30–50 ppm	Protects chlorine from UV degradation.
Salt (saltwater only)	2,700–3,500 ppm	Low: chlorinator underproduces.

Saltwater vs Chlorine Pools

Saltwater pools still use chlorine — a salt chlorine generator (SWG) electrolyzes the salt water to produce chlorine automatically. Saltwater pools are gentler on skin and eyes, require fewer chemical purchases, and have lower long-term operating costs, but the SWG equipment costs $600–$2,000 upfront and may need replacement every 3–7 years.

Note: Chemical dosing recommendations are starting estimates based on industry guidelines. Always test your water chemistry before adding chemicals, add chemicals with the pump running, and follow all manufacturer safety instructions. Never mix pool chemicals.

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