Pool Volume Calculator

Q: How many gallons is a standard swimming pool?

A 12×24 ft pool at 5 ft average depth holds about 10,800 gallons. A 20×40 ft pool holds approximately 36,000 gallons.

Q: How do I calculate pool volume for an irregular shape?

Divide the pool into simpler shapes, calculate each volume separately, then add them together.

Q: Why do I need to know my pool volume?

Pool volume determines chemical dosing. Incorrect amounts of chlorine or pH adjuster can harm swimmers or damage equipment.

Q: How much water does a pool lose to evaporation?

Typically 1–2 inches per week in summer, roughly 500–1,000 gallons per week for an average pool.

Calculate swimming pool volume in US gallons and litres — choose your pool shape.

Length (ft)

Width (ft)

Average Depth (ft)

Diameter (ft)

Average Depth (ft)

Length (ft)

Width (ft)

Average Depth (ft)

Long Section Length (ft)

Long Section Width (ft)

Short Section Length (ft)

Short Section Width (ft)

Average Depth (ft)

Cubic Feet

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US Gallons

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Litres

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How to Calculate Pool Volume

Pool volume depends on the shape and average depth. For a rectangular pool, multiply length × width × average depth to get cubic feet, then multiply by 7.48 for US gallons. Round pools use the circle formula: π × radius² × depth. Oval pools use the ellipse formula: π × (length/2) × (width/2) × depth. L-shaped pools are calculated as two rectangles added together. Always use the average depth — if your pool slopes from 3 ft at the shallow end to 7 ft at the deep end, the average depth is 5 ft. Knowing your pool volume is essential for accurate chemical dosing. Adding too little chlorine leaves bacteria untreated; adding too much can irritate swimmers and damage equipment. Use this calculator before adding any pool chemicals.

Frequently Asked Questions

How many gallons is a standard swimming pool?

A standard 12×24 ft rectangular pool at 5 ft average depth holds about 10,800 gallons. A large 20×40 ft pool holds approximately 36,000 gallons.

How do I calculate pool volume for an irregular shape?

Divide the pool into simpler shapes (rectangles, circles), calculate each volume separately, then add them together. Use average depth for sloped-bottom pools.

Why do I need to know my pool volume?

Pool volume determines chemical dosing. Using the wrong amount of chlorine, algaecide or pH adjuster can damage pool equipment or irritate swimmers.

How much water does a pool lose to evaporation?

A typical outdoor pool loses 1–2 inches of water per week to evaporation in summer — roughly 500–1,000 gallons per week for an average pool.

Pool Volume Calculator

How to Calculate Pool Volume

Frequently Asked Questions

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