Pool Volume Calculator
Convert your pool dimensions into gallons for dosing and heating.
What you'll need to order
- pool chemicals
- test kit
- pool heater
Prices vary by region and haul distance. Get quotes from at least two local suppliers.
How this calculator works
gallons = length × width × average depth × shape factor × 7.48
A cubic foot holds 7.48 US gallons. The shape factor approximates the area lost on curved pools — 0.85 for oval and kidney shapes, 0.79 for circular.
Worked example
With length 32 ft, width 16 ft, average depth 5 ft, shape factor 1 , this calculator returns 19150.13 gal.
Pool volume by average depth
Figures below assume length 32 ft × width 16 ft × shape factor 1 . Change any measurement in the calculator to get your own numbers.
| Average depth | Pool volume (gal) | Cubic feet (cu ft) |
|---|---|---|
| 3 ft | 11,490 | 1,536 |
| 3.5 ft | 13,405 | 1,792 |
| 4 ft | 15,320 | 2,048 |
| 4.5 ft | 17,235 | 2,304 |
| 5 ft | 19,150 | 2,560 |
| 6 ft | 22,980 | 3,072 |
| 8 ft | 30,640 | 4,096 |
A 32 by 16 ft rectangular pool. Average depth is what matters, not the deep end — add shallow and deep depths and halve them.
Volume of common pool sizes
| Job | Size | Pool volume |
|---|---|---|
| Above-ground round, 18 ft | 18 ft × 18 ft × 4 ft × 0.79 | 7,659 gal |
| Above-ground round, 24 ft | 24 ft × 24 ft × 4.5 ft × 0.79 | 15,318 gal |
| Small rectangular, 12x24 | 24 ft × 12 ft × 4.5 ft × 1 | 9,695 gal |
| Standard in-ground, 16x32 | 32 ft × 16 ft × 5 ft × 1 | 19,150 gal |
| Large in-ground, 20x40 | 40 ft × 20 ft × 5.5 ft × 1 | 32,914 gal |
| Kidney shape, 15x30 | 30 ft × 15 ft × 4.5 ft × 0.85 | 12,876 gal |
Shape factor corrects a rectangular estimate: 1 for a rectangle, 0.85 for kidney and oval shapes, 0.79 for a circle.
Shape factors
| Type | Multiplier | Notes |
|---|---|---|
| Rectangle or square | 1.00 | No correction needed |
| Oval | 0.89 | Length and width at the widest points |
| Kidney | 0.85 | Average the two widths first |
| Circle | 0.79 | Use the diameter for both dimensions |
| Free-form | 0.85 | A reasonable estimate; measure again if dosing matters |
Getting volume wrong is why pool chemistry goes wrong. Every dose on a chemical label is per 10,000 gallons, so a 20% volume error is a 20% dosing error, every time.
Frequently asked questions
How many gallons is a 16x32 pool?
About 19,000 gallons at an average depth of 5 feet. Multiply length by width by average depth to get cubic feet, then multiply by 7.48.
How do I calculate average pool depth?
Add the shallow end depth to the deep end depth and divide by two. For a pool with a long transition slope, measure at three points and average those instead.
How many gallons is a 24 foot round pool?
Roughly 13,500 gallons at 4.5 ft deep. Round pools use a 0.79 shape factor against the square of the diameter.
How many gallons is my pool?
Multiply length by width by average depth in feet, then by 7.48. A 32 by 16 ft pool averaging 5 ft deep holds about 19,150 gallons.
How do I find average depth?
Add the shallow end depth to the deep end depth and divide by two. For a pool with a long flat shallow section, weight it by the area at each depth instead — a simple average overstates volume.
Why does volume matter for pool chemicals?
Every dose is specified per 10,000 gallons. Getting the volume wrong by 20% means every chlorine, acid and stabiliser addition is wrong by the same margin, which is how pools end up chronically out of balance.
How many gallons in a cubic foot of water?
Just under 7.5 — precisely 7.48052 US gallons, weighing about 62.4 lb. That weight is worth remembering when calculating loads on a deck or structure.