Aquarium Volume Calculator
Tank gallons and liters from your dimensions: rectangle, cylinder, hex and more.
Volume
28.05 gal
Liters
106.2 L
This is the full water volume; actual capacity is a bit lower once you add substrate, rocks and the fill line.
Advertisement
Why volume matters
Your tank's true volume drives everything downstream: how many fish it can safely hold, what size filter and heater you need, and how much water to change. Knowing the real gallons (not the number on the box, which is often rounded) is the first step before stocking.
Common tank sizes
Frequently asked questions
How do you convert dimensions to gallons?
Volume in cubic inches divided by 231 gives US gallons. For a rectangular tank that's length Γ width Γ height Γ· 231; other shapes use the matching geometry formula.
Is the calculated volume the same as water volume?
It's the full interior volume. Real water volume is a bit lower once you account for substrate, rocks, decor and leaving the water line below the rim.
How many gallons is my tank in liters?
Multiply US gallons by 3.785 to get liters.
Keep going with the same pet
Got your gallons? Use the stocking calculator to see how many fish your tank can safely hold.
Your dog's age in human years, breed-size adjusted, not the Γ7 myth.
Your cat's age in human years using the real feline curve, not the Γ7 myth.
How much to feed: daily calories and cups by weight, activity and life stage.
Bioload-based stocking guidance, not the oversimplified 1-inch-per-gallon rule.