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.
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.
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.
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.
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.
Estimate only. Results reflect your inputs and standard formulas. Double-check important decisions independently.