This formula is a good method of calculating how many gallons of water in your Swimming Pool or your Water Garden (Ponds).  

How to calculate gallons!

  1. Calculate average depth.
    (Deep end depth + shallow end depth) then divide by two.

  2. Calculate average length and then average width.

  3. Then multiply as shown below.

    Average Length X Average Width
    Then multiply results by Average Depth.
    Then multiply results by 7.5.
    EXAMPLE:
    Deep End =   8'
    Shallow   =   3'
    8'+3' =11 (then divide by 2 = 5.5' avg. depth.)
    Average length = 32'
    Average Width  = 15'
    32 X 15 = 480
    480 X 5.5 = 2640
    2640 X 7.5 = 19,800 gallons (est.)
     

    In order to figure out the correct amount of chemicals to add to your pool, first you have to know how much water your pool can hold. Begin by calculating your pool's depth, then you can determine capacity by using one of the formulas from this chart:

    AVERAGE DEPTH = SHALLOW END DEPTH + DEEP END DEPTH / 2


    RECTANGLE POOLS:
    length x width x average depth x 7.5 = *total gallons


    ROUND POOLS:
    circular diameter x diameter x average depth x 5.9 = *total gallons


    OVAL POOLS:
    full width x full length x average depth x 5.9 = *total gallons


    SLOPING SIDES:
    if your pool has sloping sides, multiply the final figure by .85.