Pool Volume Calculator
Volume of rectangular, oval and round swimming pools — in US gallons and liters, with fill time and a rough shock-chlorine estimate.
For sloped floors use (shallow + deep) / 2.
Garden hose: 5–10. Higher flow = faster fill estimate.
Shock estimate: about 1 lb of calcium hypochlorite (65%) per 10,000 gallons for a standard shock dose — always follow the product label.
How the calculation works
Rectangular: V = L × W × D. Round: V = π × r² × D. Oval: V = π × (L/2) × (W/2) × D, where D is the average depth. The result is converted with 1 ft³ = 7.48052 US gallons and 1 US gallon = 3.78541 liters.
Worked example: a 40 ft × 20 ft pool with 5 ft average depth holds 4,000 ft³ = 29,922.08 gallons = 113,267.39 liters. At 10 GPM it fills in 2 days, 1 hr, 52 min.
Frequently asked questions
How do you calculate the volume of a rectangular pool?
Multiply length times width times average depth: V = L x W x D. For example, a 40 ft x 20 ft pool with 5 ft average depth holds 4,000 cubic feet, which is 29,922.08 US gallons or 113,267.39 liters.
How do you calculate the volume of a round pool?
Use V = pi x r squared x average depth, where r is half the diameter. For example, a 24 ft diameter pool with 4 ft average depth holds 1,809.56 cubic feet, which is 13,536.43 US gallons.
How do you calculate the volume of an oval pool?
Use V = pi x (L/2) x (W/2) x average depth. For example, a 33 ft x 18 ft oval pool with 4 ft average depth holds 1,866.11 cubic feet, which is 13,959.44 US gallons.
How many gallons are in a cubic foot of water?
One cubic foot holds 7.48052 US gallons, which is the rounded value of 1728/231 since one US gallon is defined as exactly 231 cubic inches. In metric, one cubic foot equals 28.3168 liters.
How long does it take to fill a pool?
Divide the pool volume by your fill rate: time = gallons / GPM. For example, a 29,922.08 gallon pool filled at 10 gallons per minute takes 2,992.2 minutes, which is 2 days, 1 hr, 52 min (49.87 hours).
How do you calculate pool volume in liters and cubic meters?
Compute the volume in cubic meters, then multiply by 1,000 to get liters. For example, a 12 m x 6 m pool with 1.4 m average depth holds 100.8 cubic meters, which is 100,800 liters. One cubic meter also equals 264.172 US gallons.
What is average depth and how do I measure it?
Average depth is the depth you plug into the formula. For a pool with a sloped floor, measure the shallow end and the deep end and take the mean: (shallow + deep) / 2. For a flat floor, just measure the depth directly.
How much shock chlorine does my pool need?
As a rough starting dose, one pound of calcium hypochlorite 65 percent treats about 10,000 gallons of water for a standard shock. For example, a 29,922.08 gallon pool needs about 2.99 pounds. Always follow the product label, because the exact dose depends on your current chlorine and CYA levels.
How do I convert gallons to liters?
Multiply US gallons by 3.78541 to get liters, or divide liters by 3.78541 to get gallons. For example, 29,922.08 gallons equals 113,267.39 liters.
Is the oval pool formula exact?
The oval formula treats the pool as an ellipse, which matches most manufactured oval pools closely. For freeform kidney-shaped pools the ellipse formula is only an approximation; break the shape into rectangles and ellipses for a better estimate, or consult the pool builder specification.
Free tool by NRTechStudio