Pool Volume Calculator
Find your swimming pool's volume in gallons.
Average of shallow and deep ends
Results update as you type.
How it works
Knowing your swimming pool's volume is essential for dosing chemicals, sizing pumps and heaters, and estimating fill costs, and this calculator finds it. You enter the pool's length, width, and average depth in feet, and it returns the volume in gallons, liters, and cubic feet. For a rectangular pool, the volume in cubic feet is simply length times width times depth, and converting to gallons uses the fact that one cubic foot of water is about 7.48 US gallons. The key subtlety is depth: most pools are not a uniform depth but slope from a shallow end to a deep end, so you should use the average depth, roughly the shallow depth plus the deep depth divided by two, to get an accurate volume. Getting the volume right matters most for pool chemistry, since chlorine, pH adjusters, algaecides, and other treatments are dosed per a specific number of gallons, and guessing can lead to unsafe or ineffective water. It also helps you estimate how long the pool takes to fill and the water cost. This calculator assumes a rectangular pool; oval, round, or irregular pools need different shape formulas or can be approximated. Enter your pool's length, width, and average depth to compute its volume.
Gallons = length × width × avg depth × 7.48
For a rectangular pool, volume in cubic feet is length times width times average depth. Multiplying cubic feet by 7.48 gives US gallons, since one cubic foot holds about 7.48 gallons, and by 28.32 gives liters. Using the average depth accounts for pools that slope from a shallow to a deep end.
Source:Volume geometry
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter length, width and average depth.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Volume updates instantly as you type — no button to press.
Frequently asked questions
How do I calculate my pool's volume?
Multiply the length by the width by the average depth in feet to get cubic feet, then multiply by 7.48 to get US gallons. For a 32 by 16 foot pool averaging 5 feet deep, that is 2,560 cubic feet, or about 19,150 gallons. The calculator does this and also shows liters.
What depth should I use?
Use the average depth, not the deepest point. Since most pools slope from a shallow end to a deep end, add the shallow depth and the deep depth and divide by two for a reasonable average. Using only the deep-end depth would overstate the volume significantly and throw off chemical dosing.
Why do I need to know my pool's volume?
Pool volume is essential for correctly dosing chemicals like chlorine, pH adjusters, and algaecides, which are all measured per a given number of gallons. Too little leaves water unsafe or cloudy; too much wastes product or irritates swimmers. Volume also helps size pumps and heaters and estimate fill time and water cost.
How many gallons is a cubic foot of water?
One cubic foot of water equals about 7.48 US gallons. That is why the volume in cubic feet is multiplied by 7.48 to get gallons. For liters, one cubic foot is about 28.32 liters. The calculator applies these conversions automatically so you get the volume in all three units.
Does this work for round or oval pools?
This calculator assumes a rectangular pool. Round, oval, and irregular pools use different area formulas, so multiplying length by width would overestimate them. For a round pool, use pi times the radius squared times depth; for oval or freeform shapes, approximate the surface area first, then multiply by average depth.