Swimming Pool Volume Calculator: How Much Water is in Round, Rectangle & Freeform Backyard Pools

Are you wondering how many gallons of water are in your pool or spa? If you plan to apply chemicals, use a phosphate reducer or add an enzyme clarifier, calculating the volume is an important first step. 

Before you start, you'll need to know four different numbers: the length, width, average depth, and a multiplier for your type of pool.

For a standard rectangular pool:
Length x Width x Average Depth x 7.48 = Volume in Gallons

For an oval or round pool or hot tub:
Length x Width x Average Depth x 5.9 = Volume in Gallons

Once you know the pool volume, you can confidently start using your water treatment products like Orb-3 Pool Enzymes and Orb-3 DropOut. 

This works for your hot tub or spa as well. Just measure L x W x Avg Depth x 7.48 for an approximate volume to go by. Then use Orb-3 Spa Enzymes to minimize upsets.