40-Gallon Hexagonal Aquarium
About 151.4 liters. Convert your exact dimensions below.
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.
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About the 40-gallon hexagonal tank
A 40-gallon hexagonal aquarium holds roughly 151.4 liters of water at full volume. Because this shape is tall relative to its footprint, surface area for gas exchange is smaller than a long rectangular tank of the same volume, worth keeping in mind for stocking. Remember the usable water volume is a bit lower than the geometric volume once you add substrate, rocks and leave the water line below the rim. Enter your tank's real measurements above for an exact figure, then head to the stocking calculator before adding fish.
Frequently asked questions
How many liters is a 40-gallon tank?
About 151.4 liters (US gallons Γ 3.785).
What can I keep in a 40-gallon tank?
It depends on bioload, not just gallons. Use the stocking calculator to check specific fish against a 40-gallon volume.
Keep going with the same pet
How many fish fit a 40-gallon tank? Check the stocking calculator.
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.