Pool Volume Calculator
Calculate pool water volume.
Input
Result
What is a Pool Volume Calculator?
A pool volume calculator estimates the total water capacity of a swimming pool based on its shape (rectangular, round, or oval) and dimensions. It outputs volume in cubic feet and gallons for chemical dosing and water planning.
How to calculate pool volume manually (the formula)
Rectangular: V = l × w × d. Round: V = πr2 × d. Oval: V = π × (L/2) × (W/2) × d. For sloping bottoms, use the average depth: (shallow + deep) ÷ 2.
Example calculation
A rectangular pool is 30 ft long, 15 ft wide, with an average depth of 5 ft. Volume = 30 × 15 × 5 = 2,250 ft³. In gallons: 2,250 × 7.48 ≈ 16,830 US gallons.
Common mistakes
- Using maximum depth instead of average depth — For pools with sloping bottoms, use (shallow + deep) ÷ 2, not just the deepest point.
- Forgetting to convert cubic feet to gallons — Most pool chemical instructions use gallons. Multiply ft³ by 7.48 (US) or 6.23 (imperial).
- Mixing measurement units — All dimensions must be in the same unit (feet or meters). Do not mix feet and inches without converting.
Frequently asked questions
How do you calculate the volume of a rectangular pool?
Multiply length by width by average depth: V = l \u00d7 w \u00d7 d. Then convert cubic feet to gallons (1 ft\u00b3 \u2248 7.48 gal).
How do you calculate the volume of a round pool?
Use V = \u03c0r\u00b2 \u00d7 d, where r is radius and d is depth. Multiply pi by radius squared by depth.
How do you calculate the volume of an oval pool?
Use V = \u03c0 \u00d7 (long axis/2) \u00d7 (short axis/2) \u00d7 depth. This treats the oval as an ellipse.
How many gallons is my pool?
Calculate volume in cubic feet, then multiply by 7.48 to get US gallons, or 6.23 for imperial gallons.
What depth should I use for an average-depth pool?
Average depth = (shallow end depth + deep end depth) / 2. This gives a good estimate for sloping-bottom pools.
Why is knowing pool volume important?
Pool volume determines how much water is needed to fill it, and is essential for calculating correct chemical dosages and filter sizing.