A pool volume calculator determines how much water your swimming pool holds. Enter pool dimensions and depth to get results in liters, gallons, and cubic meters — essential for chemical dosing and water costs.
Pool volume is the total amount of water a swimming pool holds, typically measured in US gallons, liters, or cubic meters. Knowing your pool volume is essential for:
Rectangular pool: V = Length × Width × Average Depth.
Average depth = (shallow end + deep end) ÷ 2.
Example: 40 ft × 20 ft pool, shallow 3.5 ft, deep 8 ft: Average depth = 5.75 ft.
V = 40 × 20 × 5.75 = 4,600 ft³ × 7.481 = 34,413 US gallons ≈ 130,266 L.
For oval pools: V = Length × Width × Average Depth × 0.7854.
For kidney-shaped: V = (A + B) ÷ 2 × Length × Avg Depth × 0.45 (where A and B are the widths).
24 × 12 × 4 ft avg: V = 24×12×4 = 1,152 ft³ = 8,618 gal ≈ 32,623 L.
50 × 25 × 2 m: V = 2,500 m³ = 2,500,000 L = 660,430 gal.
Diameter 15 ft, depth 4 ft: V = π×7.5²×4 = 706.9 ft³ = 5,288 gal.
25 × 2.5 × 1.5 m: V = 93.75 m³ = 93,750 L = 24,771 gal.
35 free volume calculation tools — click any calculator to get started.
Answers to common questions about the pool volume calculator.
Rectangular: L × W × Avg Depth (in feet) × 7.481 = US gallons. Round: π × radius² × depth × 7.481. Or use our calculator above for instant results.
Average US water cost: ~$0.004/gallon. A 20,000 gallon pool: ~$80 to fill. Costs vary widely by location ($30-$200+). You can also hire a water truck at ~$200-500 for bulk delivery.
Most pool chemicals list dosage per 10,000 gallons. Divide your pool volume by 10,000, then multiply by the recommended dose. Example: Pool is 15,000 gal = 1.5 × the listed dose.
A typical garden hose delivers 9 gallons/minute. Time = Volume ÷ Flow Rate. A 20,000 gal pool: 20,000 ÷ 9 ÷ 60 = ~37 hours continuous.
Small pool: 5,000-10,000 gal. Average residential: 12,000-24,000 gal. Large residential: 25,000-40,000 gal. Olympic: 660,000 gal (2.5 million liters).