WeekendCalc

Pool Volume Calculator

Choose your pool shape and enter its size and depth. You get the volume in gallons and liters, and the time to fill it from a garden hose.

Your project

Same as the shallow depth if the bottom is flat (most above-ground pools).

gal/min

A garden hose delivers about 5 to 10 gallons a minute.

Results

Pool volume
22,023 US gallons
Liters
83,365 L
Cubic feet
2,944 ft³
Average depth
5.75 ft

Filling

Time to fill with a hose
40.8 hours
Time to fill with a hose
1.7 days
  • Volume = surface area × average depth × 7.48 gallons per cubic foot. Oval pools use 0.7854 (π ÷ 4) times a rectangle of the same length and width. Kidney and freeform pools are harder to estimate: use the average of several measurements.

How this calculator works

A pool is a prism, so its volume is the surface area times the average depth. For a rectangle that is length × width; for a round pool it is π × radius²; and for an oval it is π ÷ 4 times length × width. One cubic foot of water holds 7.48 US gallons. For a pool with a sloping floor, average the shallow and deep depths.

gallons = surface area × (shallow depth + deep depth) ÷ 2 × 7.48

Worked example: a 32 × 16 ft rectangular pool that is 3.5 ft deep at one end and 8 ft at the other has an average depth of 5.75 ft. Its volume is 32 × 16 × 5.75 × 7.48 = 22,020 gallons.

Tips before you buy

  • Know your volume before adding chemicals. The dose on the label is per gallon, and getting it wrong wastes money or makes the pool unsafe.
  • Use the water level, not the full depth, if the pool is not filled to the top. A pool full to the skimmer is about 4 to 6 in below the rim.
  • A hose will take days to fill a big pool. Many people have the water delivered, or check with the local water authority about fill rates and costs.
  • Use a bucket to test your hose flow. Time how long it takes to fill a 5 gallon bucket and divide.

Quick answers by size

12 ft round pool3,384 gal at 4 ft deep15 ft round pool5,288 gal at 4 ft deep18 ft round pool7,614 gal at 4 ft deep21 ft round pool10,364 gal at 4 ft deep24 ft round pool13,536 gal at 4 ft deep27 ft round pool17,132 gal at 4 ft deep30 ft round pool21,151 gal at 4 ft deep12 × 24 ft pool10,772 gal at 5 ft average depth14 × 28 ft pool14,662 gal at 5 ft average depth16 × 32 ft pool19,150 gal at 5 ft average depth18 × 36 ft pool24,237 gal at 5 ft average depth20 × 40 ft pool29,922 gal at 5 ft average depth

Tools & materials for this project

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Pool test kitPool chlorine tabletsPool vacuumPool coverSkimmer net

Frequently asked questions

How many gallons is a 15-foot round pool?

At a flat 4 ft depth, about 5,300 gallons. At 52 inches deep, it is roughly 5,700 gallons. Enter your depth above for an exact figure.

How many gallons is a 16x32 pool?

With an average depth of 5.75 ft it is about 22,000 gallons. A flat 4 ft depth would be about 15,300 gallons.

How do I measure a pool with a sloping bottom?

Measure the depth at the shallowest and deepest points and use the average. For a pool with a deeper middle section, measure at several spots and average them.

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Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.