Things You'll Need
- Flexible measuring tape
- One gallon water-safe container
- Calculator
Instructions
US/English Units (inches, gallons)
Measure the height of the tank from the inside in inches using the measuring tape. This number will be different than the outside measurement due to the glass.
Fill the tank with a one-gallon container and keep track of how many of these containers it takes to fill it, to determine the volume of the aquarium if you do not have this number already.
Convert US liquid gallons to cubic inches using a formula of volume in gallons multiplied by 231.000. This gives you the volume in inches cubed, or cubic inches.
Divide this number by the height in inches. Since volume is surface area multiplied by height (length times width time height in simpler shapes), this will give you the surface area in square inches or inches squared. The units work algebraically as cubic inches divided by inches produce square inches. This number is your surface area.
Metric Units (centimeters, liters)
Measure the height of the tank from the inside in centimeters. This number will be different than the outside measurement due to the glass.
Fill the tank with a one-liter container and keep track of how many of these containers it takes to fill it, to determine the volume of the aquarium if you do not have this number already.
Convert liters to cubic centimeters. The formula is (volume in liters) multiplied by 1000. This gives you the volume in cubic centimeters (which happens to be 1 ml, but cubic centimeters are needed for this formula).
Divide this number by the height in centimeters. Since volume is surface area multiplied by height (length times width time height in simpler shapes), this will give you the surface area in square centimeters. The units work algebraically as cubic centimeters divided by centimeters produce square centimeters. This number is your surface area.