Pool Volume Calculator
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What Your Result Means
- Volume (cubic feet or m³): The raw geometric volume of your pool based on the dimensions you entered. This is the space the water occupies.
- Gallons / Liters: The liquid capacity converted using 1 cu ft = 7.48 US gallons (imperial) or 1 m³ = 1,000 liters (metric). This is the number you need for chemical dosing, fill-time estimates, and water bills.
- Average depth matters: Most pools have a shallow and deep end. Use the average of the shallowest and deepest points for the best estimate. A pool that goes from 3 ft to 8 ft has an average depth of about 5.5 ft.
How This Calculator Works
You select a pool shape (rectangular, round, or oval), enter the dimensions and average depth, and choose imperial or metric units. For rectangular pools, volume = length × width × depth. For round pools, volume = π × (diameter/2)² × depth. For oval pools, volume = π × (length/2) × (width/2) × depth. The cubic volume is then multiplied by 7.48 for gallons or 1,000 for liters.
Quick Questions
How do I measure average depth?
Measure the depth at the shallow end and the deep end, then average them: (shallow + deep) ÷ 2. For pools with a gradual slope this gives a good estimate. If your pool has a sudden drop-off, measure at several points and average all readings.
How long will it take to fill my pool?
A standard garden hose delivers about 9 gallons per minute (540 gal/hr). Divide your pool's gallon volume by 540 to get approximate fill hours. A 15,000-gallon pool takes roughly 28 hours with one hose. Using two hoses or a fire hydrant fill service speeds this up considerably.
Why is my actual water volume different from the calculator?
This calculator uses ideal geometric formulas. Real pools have ledges, steps, benches, and irregular contours that reduce the actual volume. The calculated number is typically 5–10% higher than what you'd measure with a water meter.
What about kidney-shaped or freeform pools?
For irregular shapes, the oval formula gives a reasonable approximation. Measure the longest and widest dimensions and use the oval shape. For more accuracy, break the pool into simpler geometric sections and add the volumes together.
Sources
- EPA WaterSense (water volume measurement standards)
- NIST — SI Units (cubic meter and liter definitions)
Method & review
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.