Which pool shapes does this calculator support?

It covers rectangular pools (length × width), round pools (using the diameter), and oval pools (using both axis lengths). Each shape uses the correct surface-area formula before multiplying by depth.

What depth should I enter for a pool with a deep end?

Use the average depth, which for a pool that slopes from shallow to deep is roughly the shallow depth plus the deep depth divided by two. This gives a far more accurate volume than using a single end.

Why convert with 7.48 gallons per cubic foot?

One cubic foot of water holds about 7.48 US gallons. Multiplying the cubic-foot volume by 7.48 converts the geometric volume into the gallon figure used on most pool chemical labels.

How accurate is the gallon estimate?

It is a close approximation based on simple geometry and an average depth. Irregular shapes, steps, and curved walls can shift the true volume by a few percent, so round up slightly when dosing chemicals.

Pool Volume Calculator

Shape

Length (ft)

Width (ft)

Average Depth (ft)

Gallons7,480

Cubic Feet1,000.00

Knowing your pool's water volume is essential for dosing chemicals, sizing a heater or pump, and estimating fill costs. This pool volume calculator handles rectangular, round, and oval shapes, computing the volume in cubic feet and converting to US gallons at 7.48 gallons per cubic foot. Enter your dimensions and average depth to get an instant capacity estimate.

Formula

gallons = area × depth × 7.48

area: Surface area: length × width (rectangle), π × r² (round), or π × (L/2) × (W/2) (oval), in square feet
depth: Average water depth in feet
7.48: US gallons per cubic foot
gallons: Total water volume in US gallons

How it works

Choose the pool shape: rectangle, round, or oval.
Enter the dimensions in feet — length and width for a rectangle or oval, or the diameter for a round pool — plus the average water depth.
The calculator finds the surface area for that shape, multiplies by depth to get cubic feet, then multiplies by 7.48 to convert to gallons.

Worked example

A rectangular pool 20 ft long, 10 ft wide, with an average depth of 5 ft.

Surface area: 20 × 10 = 200 sq ft.
Cubic feet: 200 × 5 = 1,000.
Gallons: 1,000 × 7.48 = 7,480.

1,000 cubic feet, or about 7,480 US gallons.

Frequently asked questions

Which pool shapes does this calculator support?: It covers rectangular pools (length × width), round pools (using the diameter), and oval pools (using both axis lengths). Each shape uses the correct surface-area formula before multiplying by depth.
What depth should I enter for a pool with a deep end?: Use the average depth, which for a pool that slopes from shallow to deep is roughly the shallow depth plus the deep depth divided by two. This gives a far more accurate volume than using a single end.
Why convert with 7.48 gallons per cubic foot?: One cubic foot of water holds about 7.48 US gallons. Multiplying the cubic-foot volume by 7.48 converts the geometric volume into the gallon figure used on most pool chemical labels.
How accurate is the gallon estimate?: It is a close approximation based on simple geometry and an average depth. Irregular shapes, steps, and curved walls can shift the true volume by a few percent, so round up slightly when dosing chemicals.

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