Pool Volume Calculator

Volume is the pool's top-face area multiplied by the average water depth, converted to US gallons with the identity 1 ft³ of water = 7.48 gallons. Variable-depth pools use the mean of the shallow and deep ends; leave the deep end blank for a constant-depth pool.

avgDepth = (shallow + deep) / 2   (deep blank ⇒ avgDepth = shallow)

rectangle:  L × W × avgDepth × 7.48
round:      π × (diameter/2)² × avgDepth × 7.48
oval:       L × W × (π/4) × avgDepth × 7.48
kidney:     0.45 × (Width A + Width B) × Length C × avgDepth × 7.48
freeform:   Σ (part area × avgDepth × 7.48)

liters    = gallons × 3.785411784
cubic ft  = gallons / 7.48
fill cost = (gallons / 1000) × water rate

We use π = 3.14159 and the 7.48 gal/ft³ constant. Some calculators round to 7.5, landing about 0.27% higher — the gap is purely the constant. The kidney 0.45 factor is the standard industry area approximation, and the oval uses the full-axes L × W × π/4 convention. Results are planning/dosing estimates, not engineering or structural-survey volumes.

Sources: Inch Calculator — Pool Volume Calculator; Good Calculators — Pool Volume Calculator; Swim University — Pool Calculator.