Swimming Pool Volumes
Calculate Water Volume for Any Pool Shape
Calculate Your PoolKnowing your pool's water volume is essential for proper chemical treatment, heating costs, water bills, and maintenance planning. Whether you have a small backyard pool or manage an Olympic facility, accurate volume calculations ensure safe, efficient operation.
Standard Pool Volumes
| Pool Type | Typical Dimensions | US ガロン | リットル |
|---|---|---|---|
| Small backyard | 12' × 24' × 4' avg | 8,600 gal | 32,500 L |
| Medium residential | 16' × 32' × 5' avg | 19,200 gal | 72,700 L |
| Large residential | 20' × 40' × 5.5' avg | 33,000 gal | 125,000 L |
| 25-meter lap pool | 25m × 10m × 1.5m | 99,000 gal | 375,000 L |
| Olympic pool | 50m × 25m × 2m | 660,000 gal | 2,500,000 L |
Calculating Pool Volume
Rectangular Pools (Constant Depth)
Formula: Length × Width × Depth × 7.48 = ガロン
Example: 30' × 15' × 5' deep
30 × 15 × 5 × 7.48 = 16,830 gallons (63,700 L)
Rectangular Pools (Variable Depth)
Use average depth: (Shallow end + Deep end) ÷ 2
Formula: Length × Width × Average Depth × 7.48 = ガロン
Example: 40' × 20' pool, 3' shallow to 8' deep
Average depth: (3 + 8) ÷ 2 = 5.5'
40 × 20 × 5.5 × 7.48 = 32,912 gallons (124,600 L)
Circular Pool Calculation
Formula: Radius² × π × Depth × 7.48 = ガロン
Or simplified: Diameter² × 0.785 × Depth × 7.48 = ガロン
Example: 18' diameter pool, 4' deep
18² × 0.785 × 4 × 7.48 = 7,619 gallons (28,840 L)
Above-Ground Pool Standard Sizes
| Size (Diameter × Depth) | US ガロン | リットル |
|---|---|---|
| 12' × 48" | 3,400 | 12,870 |
| 15' × 48" | 5,310 | 20,100 |
| 18' × 48" | 7,650 | 28,960 |
| 21' × 52" | 11,500 | 43,530 |
| 24' × 52" | 15,000 | 56,780 |
| 27' × 52" | 19,000 | 71,920 |
Oval Pool Calculation
Formula: Length × Width × 0.785 × Average Depth × 7.48 = ガロン
Example: 15' × 30' oval, 4' deep
15 × 30 × 0.785 × 4 × 7.48 = 10,568 gallons (40,000 L)
Irregular and Freeform Pools
For kidney-shaped, L-shaped, or other irregular pools:
- Divide the pool into simpler shapes (rectangles, circles)
- Calculate each section separately
- Add the volumes together
L-Shaped Pool Example
Main section: 20' × 15' × 5' = 11,220 gal
Extension: 10' × 8' × 4' = 2,394 gal
変換先tal: 13,614 gallons (51,540 L)
Practical Applications
Chemical Dosing
Most pool chemicals are dosed per 10,000 gallons. Knowing your exact volume prevents over- or under-treatment:
- Chlorine: 1-3 ppm (parts per million)
- pH adjusters: Vary by product
- Algaecide: Typically per 10,000 gallons
Heating Costs
It takes about 8.33 BTUs to raise 1 gallon of water 1°F. A 20,000-gallon pool heated from 70°F to 80°F requires:
20,000 × 8.33 × 10 = 1,666,000 BTUs
Water Costs
Water rates are often per 1,000 gallons. Filling a 25,000-gallon pool at $5/1,000 gallons = $125 in water alone.
Volume Comparison Chart
| Pool Volume | US ガロン | Imperial ガロン | リットル | Cubic メートル |
|---|---|---|---|---|
| Small spa | 500 | 416 | 1,893 | 1.89 |
| Large spa | 1,000 | 833 | 3,785 | 3.79 |
| Small pool | 10,000 | 8,327 | 37,854 | 37.9 |
| Medium pool | 20,000 | 16,653 | 75,708 | 75.7 |
| Large pool | 40,000 | 33,307 | 151,416 | 151.4 |
| Olympic pool | 660,000 | 549,600 | 2,500,000 | 2,500 |
まとめ
Accurate pool volume calculation is fundamental for maintenance, chemical treatment, and cost planning. Use the shape-specific formulas above, convert between gallons and liters as needed, and adjust for pool features that affect actual water volume. When precision matters, measure your water meter during initial fill.