Pool Volume Calculator
The Pool Volume Calculator estimates the total volume of water in your pool based on its shape, length, width, and average depth. This tool helps homeowners and maintenance technicians determine the exact amount of water needed for filling and chemical balancing. Whether you are opening your pool for the season, adjusting chemical treatments, or sizing a new pump, this calculator provides educational results to save you time and money.
How Pool Volume Is Calculated
Pool volume represents the total cubic footage of space your pool occupies, converted into liquid measurement. We calculate this by finding the area of the pool's surface and multiplying it by the average depth to get cubic feet.
Volume = Length × Width × Average Depth × 7.48 (for Gallons)
Where:
- Length × Width = Surface area of the pool (or π × Radius² for circular pools)
- Average Depth = (Shallow End Depth + Deep End Depth) ÷ 2
- 7.48 = Gallons per cubic foot
First, measure the longest length and shortest width at the water level. Next, find the average depth by adding the shallow and deep end depths and dividing by two. Finally, multiply these dimensions together and convert cubic feet to gallons using the standard factor of 7.48. This geometric method ensures you account for every cubic foot of water.
What Your Pool Volume Means
Knowing your pool’s volume tells you exactly how much water and chemicals are needed to keep your pool safe and clean. This number is the foundation of all your maintenance tasks, ensuring you do not waste money on excess chemicals or energy.
Chemical Balancing: For a 20,000-gallon pool, knowing this specific number allows you to apply the exact amount of chlorine or shock needed, preventing algae growth and eye irritation.
Heating Efficiency: A larger volume requires more energy to heat. Understanding your volume helps you choose the right size heater and predict monthly running costs accurately.
Turnover Rate: Your pump size should match your volume to filter all water every 8 hours. If you have a 15,000-gallon pool, you need a pump capable of moving at least 31 gallons per minute.
Important
Always measure the water dimensions, not the outer deck, to avoid overestimating volume.
This calculator provides estimates for general maintenance purposes only. Actual volumes may vary due to irregular shapes, slopes, or installed features. Consult with a professional pool service for precise construction or heating engineering requirements.
Re-measure your pool seasonally to ensure your chemical treatments remain effective throughout the year.
Calculation logic verified using publicly available standards.
View our Accuracy & Reliability Framework →