Pool Volume Calculator

How to Calculate Swimming Pool Volume

Calculating your pool’s gallon capacity is the cornerstone of pool ownership. Every sanitizer recommendation (chlorine shock, salt ppm, algaecides, pH balancers) specifies dosing per 10,000 gallons of water.

Formulas by Pool Shape

1. Rectangular Pools: Gallons = Length (ft) × Width (ft) × Average Depth (ft) × 7.4805 (1 cubic foot of water contains 7.4805 US liquid gallons)

2. Round / Circular Pools: Gallons = π × r² × Depth (ft) × 7.4805 = Diameter² × Depth (ft) × 5.9

3. Oval Pools: Gallons = Length (ft) × Width (ft) × Average Depth (ft) × 5.9

Rectangular in-ground pool – calculation example

Let’s size a standard 16 ft by 32 ft residential in-ground pool:

1. Pool length: length = 32 ft.
2. Pool width: width = 16 ft.
3. Shallow end: shallow depth = 3.5 ft.
4. Deep end: deep end = 8.5 ft.
5. Average depth: average depth = (3.5 + 8.5) / 2 = 6.0 ft.
6. The calculation results are available for you: pool capacity = 22,990 US gallons (87,027 Liters / 3,072 cu ft).

💡 When measuring depth, measure up to the midpoint of the skimmer tile line, not to the top edge of the pool coping stone.

Calculating Average Depth

If your pool floor slopes uniformly from the shallow end to the deep end:

Average Depth = (Shallow Depth + Deep Depth) / 2

If the pool has an extended shallow play shelf (e.g. 50% shallow at 3.5 ft, 50% deep at 8 ft), calculate each section as a separate volume and add them together for maximum precision.