How Many Gallons Is Your Pool, and What Dose Does It Need?
Every chemical dose starts with an honest gallon count. This calculator uses the real geometry (ellipse area for ovals, the industry 0.75 factor for free-form shapes), then doses with the same mass-balance formula pool operators use.
How the math works
Volume: surface area x average depth x 7.48 gallons per cubic foot. Rectangles use length x width; round pools use pi x r squared; true ovals use the ellipse formula (pi/4 x length x width); kidney and free-form pools multiply length x width by the industry 0.75 correction. Dosing: pounds of chemical = (target ppm minus current ppm) x gallons x 8.34 / (1,000,000 x available strength). Chlorine targets 1 to 3 ppm free chlorine, shock aims for 10 ppm, stabilizer (CYA) 30 to 50 ppm, and salt systems 3,200 ppm. The shock guide and salt system guide explain when and why, and types of pools covers the volume differences by construction.