Aquarium Volume Calculator
Calculate how many gallons and liters a rectangular aquarium holds from its length, width, and height in inches.
- Liters
- 212.4
Formula: V (gal) = L × W × H / 231
About Aquarium Volume Calculator
Aquarium Volume Calculator is a free online calculator that gives you an instant, accurate result as you type. Calculate how many gallons and liters a rectangular aquarium holds from its length, width, and height in inches.
The calculation uses the standard formula V (gal) = L × W × H / 231 and updates live with every change to the inputs. Everything runs client-side in your browser — fast, private, and free to use as often as you like.
One US gallon equals exactly 231 cubic inches, which is where the divide-by-231 rule for tank sizing comes from.
Frequently Asked Questions
Is Aquarium Volume Calculator free to use?
Yes. Aquarium Volume Calculator is completely free, with no sign-up, no downloads, and no usage limits. You can use it as many times as you like on any device with a web browser.
How accurate is this calculator?
The calculator applies the standard formula (V (gal) = L × W × H / 231) with full floating-point precision and rounds only the displayed result. For most practical purposes the results are exact.
Why does my tank hold less water than calculated?
The calculation uses outside dimensions and a completely full tank. Glass thickness, substrate, decorations, and the fill line below the rim all reduce the real water volume, often by 10-15%.
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