Pool Volume Calculator: Know Your Pool’s Gallons Instantly
When it comes to maintaining a clean, safe, and well-balanced swimming pool, knowing how many gallons of water your pool holds is essential. Whether you’re adding chemicals, planning to drain your pool, or just curious about its size, a pool volume calculator is your go-to tool.
In this blog, we’ll walk you through why calculating pool volume is important, how to use a pool gallon calculator, and some easy formulas you can use if you prefer to do it manually.
Why You Need to Know Your Pool Volume
Understanding your pool’s volume is critical for:
- Chemical dosing: Proper chlorine, pH balancers, and algaecides require precise measurements.
- Heating efficiency: Pool heaters work better when tailored to the correct water volume.
- Water conservation: Helps in estimating refills, backwashes, or draining.
- Troubleshooting: Diagnosing issues like cloudiness or algae is easier when you know the water volume.
What Is a Pool Volume Calculator?
A pool volume calculator is an online tool that helps you estimate the number of gallons of water in your swimming pool based on its dimensions and shape. All you have to do is enter a few measurements, and the tool will do the math for you in seconds. Contact our professionals if you are confused
How to Use a Pool Gallon Calculator
Depending on your pool’s shape—rectangle, round, oval, or custom—you’ll need the following details:
For Rectangular Pools:
- Length (in feet)
- Width (in feet)
- Average depth (shallow + deep / 2)
Formula:
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Volume = Length × Width × Average Depth × 7.5
Example:
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30 ft × 15 ft × 5 ft = 2,250 cubic feet
2,250 × 7.5 = 16,875 gallons
For Round Pools:
- Diameter
- Average depth
Formula:
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Volume = Diameter × Diameter × Average Depth × 5.9
For Oval Pools:
- Length
- Width
- Average depth
Formula:
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Volume = Length × Width × Average Depth × 6.7
These multipliers (7.5, 5.9, 6.7) convert cubic feet to gallons based on the pool shape.
Manual vs Online Calculation
While the formulas work well for standard shapes, irregular or kidney-shaped pools may be harder to calculate manually. That’s where an online pool gallon calculator comes in handy—it considers curve estimates, slope variation, and other irregular features.
Pro Tip: Don’t Forget to Account for Sloped Bottoms
If your pool has a deep end and shallow end, take both measurements and average them:
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(Shallow Depth + Deep Depth) ÷ 2 = Average Depth
This ensures your volume estimate is as accurate as possible.
Table of Common Pool Sizes and Gallon Estimates
| Pool Size (ft) | Average Depth (ft) | Estimated Gallons |
| 12×24 | 5 | ~10,800 gallons |
| 15×30 | 5 | ~16,875 gallons |
| 18×36 | 5 | ~24,300 gallons |
| 20×40 | 5 | ~30,000 gallons |
Use this table for quick reference, but for precision, the calculator is your best bet.
After Knowing Your Volume – What’s Next?
Once you know the total gallons in your pool, you can:
- Add the correct amount of chlorine or pool shock
- Balance your pH and alkalinity effectively
- Avoid overspending on chemicals
- Maintain a safer swimming environment for your family
Other Handy Tools to Use Alongside
- Pool Chemical Calculator
- Heating Cost Estimator
- Saltwater Pool Conversion Estimator
These work best when you start with an accurate pool volume calculation.
Final Thoughts
A pool volume calculator is more than just a convenience—it’s an essential tool for pool owners. From keeping your water safe to helping you budget your maintenance, knowing your pool’s volume empowers you to manage your pool like a pro.
So, whether you prefer to do the math yourself or use a reliable pool gallon calculator online, the important thing is to get your pool measurements right and keep your backyard oasis in top shape.
Next Topic- Understanding Cyanuric Acid in Pools: A Comprehensive Guide
