Volume

Ideally, the manufacturer or your spa or hot tub can tell you the exact volume. However, you can estimate it using the following formulas, using the inner dimensions and average depth of your water:

Rectangular

Gallons = Length x Width x Depth x 7.5 (using feet)

Liters = Length x Width x Depth x 1000 (using meters)

Circular

Gallons = (Diameter ÷ 2) x (Diameter ÷ 2) x Depth x 23.55 (using feet)

Liters = (Diameter ÷ 2) x (Diameter ÷ 2) x Depth x 1000 (using meters)

• If you’re not sure of your spa’s capacity, you can estimate it using this tool.