Pool Volume Calculator
Calculate a pool's water volume in gallons and liters for rectangular, round, or oval shapes using the dimensions and average depth — the number you need to dose chemicals correctly and size a heater or pump.
How to Use
- Choose the pool shape — rectangular, round, or oval — to show the right dimension fields.
- Enter the dimensions in feet: length and width for rectangular, diameter for round, or the long and short axes for oval.
- Enter the average water depth in feet — for a sloped bottom, use (shallow end + deep end) ÷ 2.
- Read the volume in both US gallons and liters in the results panel.
- Check the step-by-step Show Work below to see how the area and depth combine.
Show Work
Conversions
About the Pool Volume Calculator
Meet the Pool Volume Calculator: a free, no-fuss tool for building, materials estimation and site work with nothing to install and no sign-up. Calculate a pool's water volume in gallons and liters for rectangular, round, or oval shapes using the dimensions and average depth — the number you need to dose chemicals correctly and size a heater or pump.
How it works
Put each value in its box and read the answer as you go. Because it recalculates live, you can play with the inputs to see how each one moves the result — handy for checking your own working or planning ahead. Everything happens on your device, so it is fast and private.
Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.
Frequently Asked Questions
How do I find my pool's average depth?
If the bottom slopes, add the shallow-end depth to the deep-end depth and divide by two. For example, a pool that is 3 feet at the shallow end and 7 feet at the deep end has an average depth of 5 feet. Pools with a flat bottom just use that single depth.
Why do I need to know my pool volume?
Almost every pool task depends on it. Chemical doses — chlorine, algaecide, shock, pH adjusters — are all measured per so many gallons, and getting the volume wrong means over- or under-treating the water. You also need it to size a heater, pump, and filter and to estimate the cost of filling the pool.
How does the calculator handle round and oval pools?
It uses the standard area formulas: a round pool's area is π × radius², and an oval's is π × (long axis ÷ 2) × (short axis ÷ 2). Multiplying that surface area by the average depth gives cubic feet, which the tool converts to gallons and liters.
How many gallons is a cubic foot of water?
One cubic foot holds about 7.48 US gallons, or roughly 28.3 liters. The calculator works in cubic feet from your dimensions and then converts, so you get a practical gallon figure for chemical dosing and a liter figure for metric products.
Is the volume exact?
It is a close estimate for a uniform-shape pool. Real pools with curved walls, attached spas, beach entries, or compound slopes will differ a little. For chemical dosing the estimate is plenty accurate; for filling-cost or precise turnover calculations, round conservatively and verify against your pump and meter.
How do I use the Pool Volume Calculator?
Simply type your numbers and read the result, which refreshes the instant you change something. There is nothing to submit and nothing to wait for.
Do I need to install or sign up for anything?
Not at all — it runs in the browser with nothing to install and no account. After it loads once, it even works without an internet connection.
Is my information private?
Yes. Everything happens in your browser. Nothing you type is sent to a server or saved anywhere.
Common Use Cases
Dosing pool chemicals
Get the gallon figure that chlorine, shock, and pH products are measured against so you treat the water correctly.
Sizing a heater or pump
Know the water volume to pick a heater, pump, and filter that can turn the whole pool over efficiently.
Estimating fill cost
Convert volume to gallons to estimate the water bill or truck delivery needed to fill the pool.
Comparing pool shapes
Try rectangular, round, and oval shapes to see how design choices change the water volume you maintain.
Planning a new pool
Check the volume a planned size will hold before building so the equipment and chemical budget are realistic.
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