Calculating Aquarium Volume
How Can I Figure Out How Much Water My Fish Tank Holds?
(The First Tank Guide)
Use this simple form to convert the dimensions of your aquarium (in inches or centimeters) to a close approximation of its volume (in both U.S. gallons and liters) quickly and easily. All you need is to measure your fish tank's length (from side to side), height (from top to bottom of the tank), and depth (from front to back) and you can figure out how much water your aquarium holds!
This form will convert tank dimensions for your rectangular fish tank in either centimeters or inches to both gallons and liters. This conversion form can help you to determine appropriate tank population, and whether you have enough space for the fish you are planning on getting.
The results from this form will be approximate due to possible errors, inconsistencies, or inaccuracies in your measurements, and due to both rounding and the use of approximated conversion values in the calculations. I am converting at 2.54 centimeters per inch, 231 cubic inches in a gallon, and 3.89 liters in a gallon if you wish to check the calculations yourself.
If your tank is not rectangular, such as a bowfront (sometimes called eurostyle) or hexagonal tank, you can use the average of the questionable dimension to calculate your volume. For example, if your hex tank is 10" wide at the narrowest and 14" wide at the widest, you can use the average of 12" for the width to get a good idea of the volume of your tank.