Question 1

How do I calculate my aquarium's volume?

Accepted Answer

For a rectangular tank, multiply length × width × height (in inches) and divide by 231 to get US gallons, or in cm divide by 1000 for liters. This tool does it automatically and also subtracts the typical 10-15% displaced by substrate and decorations.

Question 2

How accurate is the calculated aquarium volume?

Accepted Answer

The geometric calculation is exact for the tank's interior dimensions. Actual water volume is usually 10-20% less because of substrate (gravel/sand), rocks, driftwood, filters and the fact that tanks are rarely filled to the very top. This tool shows both the raw and realistic water volumes.

Question 3

How many fish can I put in my aquarium?

Accepted Answer

A common guideline is 1 inch of adult fish per gallon of water (or 1 cm per 2 liters) for small community fish. Reduce stocking for larger or territorial species, and always account for the adult size of the fish, filtration capacity and water change routine.

Question 4

How much does aquarium water weigh?

Accepted Answer

Water weighs about 8.34 lb per US gallon (1 kg per liter). A filled 55-gallon tank holds about 459 lb of water alone — plus the weight of glass, substrate and decorations. Always check that your floor or stand can support the total weight.