Pool Volume Calculator
Compute Pool Volume with exact geometric formulas. Enter the required dimensions to see area, perimeter, or volume alongside step-by-step derivations.
Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy
Pool Volume Calculator Formula
Volume = Length × Width × Avg Depth × 7.48 (gallons per cu ft)
For rectangular pools: Volume = L × W × D × 7.48. For circular pools: Volume = π × r² × D × 7.48 (where r = diameter ÷ 2). For oval pools: Volume = π × (L/2) × (W/2) × D × 7.48. All dimensions in feet; multiply by 7.48 to convert cubic feet to gallons. For liters, multiply gallons by 3.785.
Pool Volume Calculator — Worked Examples
Example 1: Standard Rectangular Pool
Problem:A rectangular pool 30 ft long, 15 ft wide, with an average depth of 5 ft. Fill rate: 12 GPM.
Solution:Volume = 30 × 15 × 5 = 2,250 cu ft\nGallons = 2,250 × 7.48 = 16,830 gallons\nLiters = 16,830 × 3.79 = 63,783 liters\nFill time = 16,830 / 12 = 1,403 min = 23.4 hours
Result:16,830 gallons | 63,783 liters | 23.4 hrs to fill
Example 2: Circular Pool
Problem:A circular above-ground pool with 18 ft diameter and 4 ft depth. Fill rate: 8 GPM.
Solution:Volume = π × (9)² × 4 = 1,017.9 cu ft\nGallons = 1,017.9 × 7.48 = 7,614 gallons\nLiters = 7,614 × 3.79 = 28,856 liters\nFill time = 7,614 / 8 = 952 min = 15.9 hours
Result:7,614 gallons | 28,856 liters | 15.9 hrs to fill
Pool Volume Calculator — Frequently Asked Questions
How do I calculate the average depth of my pool?
For pools with a uniform slope: Average depth = (Shallow end depth + Deep end depth) ÷ 2. For example, if your shallow end is 3 feet and deep end is 8 feet, average depth = (3 + 8) ÷ 2 = 5.5 feet. For pools with a hopper bottom or multiple depth changes, divide the pool into sections, calculate each section's average depth, and use a weighted average based on the surface area of each section.
How many gallons does a typical pool hold?
Small residential pools (12×24 feet, 5 ft avg depth): ~10,800 gallons. Average residential pools (16×32 feet, 5.5 ft avg depth): ~21,000 gallons. Large residential pools (20×40 feet, 5.5 ft avg depth): ~33,000 gallons. Olympic pools (164×82 feet, 6.5 ft avg depth): ~660,000 gallons. Above-ground round pools (15 ft diameter, 4 ft depth): ~5,300 gallons. Hot tubs typically hold 300-500 gallons.
How long does it take to fill a pool?
A standard garden hose delivers 4-12 GPM (gallons per minute). At 9 GPM average, a 15,000-gallon pool takes approximately 28 hours to fill. A fire hydrant delivers 500-1,500 GPM. Water delivery trucks hold 6,000-8,000 gallons. Multiple hoses or a larger supply line reduces fill time proportionally. Check with your water company about bulk water rates — some offer flat fees for pool fills that are cheaper than metered water.
How much chlorine does my pool need?
To maintain 1-3 ppm free chlorine: add about 6 oz of liquid chlorine (12.5% sodium hypochlorite) per 10,000 gallons to raise chlorine 1 ppm. For granular chlorine (calcium hypochlorite 65%): use about 2 oz per 10,000 gallons per 1 ppm increase. Chlorine demand is higher in summer, after heavy rain, and with high bather loads. Test chlorine levels 2-3 times per week and adjust as needed.