Aquarium volume calculator
Find how many gallons your tank holds, at the water line you really fill it to.
Actual water in the tank
0gallons
- In liters
- 0 L
- Filled to the brim, empty of gravel
- 0 gal
Enter your measurements to see the volume.
How the volume is worked out
Volume is the area of the base times the height. In inches that gives cubic inches, and 231 cubic inches make one US gallon. A 20 by 10 by 12 inch tank is 2,400 cubic inches, or 10.4 gallons.
Measure the outside of the tank and the answer runs a little high, because the glass takes up room. Measure inside the glass if you want it exact.
Why your tank holds less than its name
Nobody fills a tank to the brim, and gravel, rocks and wood all push water out. A “55 gallon” tank usually holds 45 to 50 gallons of actual water. Use that lower number when you dose medication or water conditioner.
When you enter a gravel depth, the calculator assumes about a third of the gravel bed is water sitting in the gaps between grains.