Pool Volume Calculator
Before you can dose chlorine, shock, pH, or alkalinity correctly, you need an accurate pool volume. Enter your pool's length, width, and depth in feet or meters to get the volume in gallons, liters, and cubic feet — works for rectangle, round, oval, and kidney-shaped pools, with support for separate shallow and deep end depths.
Your pool volume will appear here
Enter your pool dimensions, then click calculate.
Quick Answer
Multiply length × width × average depth × 7.5 to get gallons for a rectangular pool. Round and kidney-shaped pools hold less water than their length and width suggest, so this calculator applies a shape correction automatically.
How It Works: Formula & Variables
Gallons = Length × Width × Average Depth × 7.5 × Shape Factor
- Rectangle / square
- shape factor = 1.0
- Round / oval
- shape factor = 0.89
- Kidney / freeform
- shape factor = 0.86
- Shallow/deep end pools
- average depth = (shallow + deep) / 2
- 1 cubic foot of water
- ≈ 7.48 gallons (rounded to 7.5 for pool math)
Worked Examples
Example 1: Rectangular pool, single depth
A 32 ft × 16 ft pool with a constant 5 ft depth: 32 × 16 × 5 × 7.5 = 19,200 gallons.
Example 2: Round pool, shallow and deep end
A 24 ft round pool with a 3 ft shallow end and an 8 ft deep end: average depth = (3 + 8) / 2 = 5.5 ft. 24 × 24 × 5.5 × 7.5 × 0.89 ≈ 21,150 gallons.
Key Concepts
Average depth, not max depth: Using the deep end depth for the whole pool will overestimate volume and lead to over-dosing chemicals.
Shape factor: A round or kidney pool with the same length and width as a rectangle holds noticeably less water — the corners that would exist in a rectangle simply aren't there.
Gallons to cubic feet: 1 cubic foot of water holds about 7.48 gallons. Pool industry math typically rounds this to 7.5 for simplicity.
Common Mistakes
Measuring in inches without converting: All measurements need to be in feet before calculating — divide inches by 12 first.
Forgetting the shape factor: Treating a round or kidney pool like a rectangle will overestimate volume by 10–15%.
Using max depth instead of average: This is the most common source of over-dosed chemicals after a volume calculation.
Frequently Asked Questions
Every chemical dose — chlorine, shock, pH adjuster, alkalinity increaser — is calculated per gallon of water. Without an accurate volume, every other pool calculation is a guess.
It is a close estimate, not an exact figure. Round and freeform pools hold less water than a rectangle with the same length and width because the corners are cut off, so the multiplier corrects for that.
Use feet, or switch to metric and use meters. If you only have inches, divide by 12 first — for example, 54 inches is 4.5 feet. If you only have centimeters, divide by 100 to get meters.
Average the depths across the zones as closely as you can, weighted by how much of the pool each zone covers. For most backyard pools, a shallow/deep average is accurate enough for dosing chemicals.
Yes. Above-ground pools are almost always a single, consistent depth, so enter that depth as the average depth.
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