Pool Volume Calculator

Calculate swimming pool water capacity in US gallons for rectangular, round, oval, and kidney pools with sloped bottom average depth.

Radius (r)

Vertical Height (h)

Pool Capacity (US Gallons)

3,871.17gal

Total Cubic Feet517.5 ft³

Pool Volume in Liters14,653.97 L

Pool Surface Water Area90 ft²

Approximate Water Weight32,285.55 lbs lbs

3D Geometric Profile

Step 1: Calculate Average Pool Water Depth5.75 ft

Formula: Avg Depth = (Shallow End Depth + Deep End Depth) / 2

Substitution: (3.5 ft + 8 ft) / 2 = 5.75 ft

For pools with a sloping floor, averaging the shallow and deep endpoints determines the effective uniform depth.

Step 2: Apply Standard Kidney Shape Approximation517.5 ft³

Formula: V_ft3 = (Width_A + Width_B) × Length × 0.45 × Avg Depth

Substitution: (6 + 14) × 10 × 0.45 × 5.75 = 517.5 ft³

The standard pool industry 0.45 multiplier accounts for the indentation and curved contour of kidney-shaped pools.

Step 3: Convert Cubic Feet to US Gallons3,871.17 US gal

Formula: Gallons = Cubic Feet × 7.4805

Substitution: 517.5 ft³ × 7.480519 = 3,871.17 US gal

There are exactly 7.4805 US liquid gallons per cubic foot of water capacity.

Quick Answer

Calculate pool volume in US gallons by multiplying surface area by average depth ((shallow + deep) / 2) and multiplying cubic feet by 7.4805. A 16×32 ft pool with average depth 5.5 ft holds approximately 21,065 US gallons.

Pool Volume Calculator Formula & Sizing Rules

Gallons = Length × Width × ((Shallow + Deep) / 2) × 7.4805

Mathematical Variable Legend for Pool Volume Calculator Formula & Sizing Rules
Variable	Definition	Standard Units
Gallons	Total water capacity in US liquid gallons	gal
Avg Depth	Average water depth: (shallow end + deep end) / 2	feet

Calculating Gallons for Accurate Pool Chemical Treatment

Knowing your exact pool volume in gallons is critical before adding chlorine shock, algaecides, or pH balancers. Underestimating volume leads to ineffective chemical treatment, while overestimating can damage pool liners and irritate swimmers.

Common Project Sizing Mistakes

Using the maximum deep-end depth instead of the true average depth
Forgetting that 1 cubic foot of water equals 7.48 gallons

Frequently Asked Questions

How do I calculate how many gallons are in my pool?▼

Find your pool surface area in square feet, multiply by average water depth ((shallow + deep) / 2), and multiply the resulting cubic feet by 7.4805.

How do you calculate a kidney-shaped pool?▼

Use the industry standard formula: (Width A + Width B) × Length × 0.45 × Average Depth × 7.4805.

How do you calculate the volume of a circular swimming pool?▼

Multiply circular surface area by average depth and convert to gallons: Gallons = π × (radius in ft)² × (average depth in ft) × 7.4805.

How many gallons are in a standard 12x24 or 16x32 pool?▼

A 12×24 ft rectangular pool with 5 ft average depth holds approx 10,772 gallons. A 16×32 ft pool with 5.5 ft average depth holds approx 21,065 gallons.

Authoritative Sources & Reference Standards

Guide for the Use of the International System of Units (SI), NIST Special Publication 811 — National Institute of Standards and Technology (NIST). Verified 2026-10-01.
Official SI unit definitions, conversion factors (Appendix B), and precision standards for cubic meters, liters, and US customary units.

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Reviewed by:VolumeCalculator.org Editorial Team·Last updated: 2026-10-01

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