Pool Volume Calculator
Calculate swimming pool volume in gallons and liters for rectangular, circular, oval, and kidney-shaped pools. See also Tank Volume Calculator, Pipe Volume Calculator, and Cubic Yard Calculator.
Pool Shape
Related Calculators:
How to Use the Pool Volume Calculator
Select your pool shape and enter the dimensions. For pools with varying depth, enter the shallow end and deep end depths — the calculator uses the average depth. For kidney or freeform pools, measure the longest length and widest width; the calculator applies a 0.75 multiplier to approximate the irregular shape. Enter a flow rate in GPM to estimate fill time. The chlorine dosage shown is for initial treatment at standard concentration.
Formula
Average Depth = (Shallow + Deep) / 2
Rectangular: V = L x W x Avg Depth x 7.48 gal/ft³
Circular: V = PI x r² x Avg Depth x 7.48
Oval: V = PI x (L/2) x (W/2) x Avg Depth x 7.48
Kidney: V = L x W x Avg Depth x 0.75 x 7.48
Example Calculation
Rectangular pool: 30 ft x 15 ft, 3 ft shallow, 8 ft deep
Average depth = (3 + 8) / 2 = 5.5 ft
Volume = 30 x 15 x 5.5 = 2,475 cu ft
Gallons = 2,475 x 7.48 = 18,513 gallons
Fill time at 10 GPM = 18,513 / 600 = 30.9 hours
Common Pool Sizes Reference
| Pool Size | Avg Depth | Gallons | Type |
|---|---|---|---|
| 12 x 24 ft | 5 ft | 10,800 | Small residential |
| 16 x 32 ft | 5.5 ft | 21,100 | Medium residential |
| 20 x 40 ft | 5.5 ft | 33,000 | Large residential |
| 18 ft round | 4 ft | 7,600 | Above-ground |
| 24 ft round | 4 ft | 13,500 | Above-ground (large) |
| 25 x 50 m | 2 m | 660,000 | Olympic competition |
Frequently Asked Questions
How many gallons is a typical residential pool?
Most residential in-ground pools hold 10,000-30,000 gallons. A common 16x32 ft pool with 5.5 ft average depth holds about 21,000 gallons. Above-ground pools typically hold 5,000-15,000 gallons depending on size.
How long does it take to fill a pool with a garden hose?
A standard garden hose delivers 5-10 GPM. A 20,000-gallon pool takes 33-67 hours (1.5-3 days) to fill with one hose. Using two hoses or a fire hydrant fill service (500+ GPM) significantly reduces fill time.
How much chlorine does my pool need?
Maintain 1-3 ppm free chlorine. For initial treatment, add about 6 oz of liquid chlorine (12.5% sodium hypochlorite) per 10,000 gallons to raise levels by 1 ppm. Shock treatment requires 1 lb of calcium hypochlorite per 10,000 gallons.
How do I measure an irregularly shaped pool?
For kidney or freeform pools, measure the longest length and widest width, then multiply by 0.75 (the shape factor). For L-shaped pools, divide into rectangles and calculate each section separately, then add the volumes together.
How much does it cost to fill a pool with water?
At average US water rates ($4-8 per 1,000 gallons), filling a 20,000-gallon pool costs $80-160. Some areas charge higher rates for large volumes. Water delivery by truck costs $200-600 for a full pool but is faster.
How much water does a pool lose to evaporation?
Pools lose 1/4 to 1/2 inch of water per day to evaporation in summer (more in hot, dry, windy climates). A 16x32 ft pool losing 1/4 inch daily loses about 80 gallons per day, or 2,400 gallons per month. Pool covers reduce evaporation by 90-95%.