Aquarium Volume Calculator
A fish tank's water volume in liters and gallons, from length, width, and height.
Every calculation runs locally in your browser. This is gross tank volume — substrate, decor, and equipment will displace some water, so the real fill volume is a bit less than shown here.
Volume
54 L
In US gallons
14.3 gal
For informational and educational purposes only — not professional advice, and not a substitute for consulting a qualified professional about your specific situation. TrueMeasureKit is not liable for decisions made based on these results. See our Terms of Service.
Why the real fill volume is always a bit less
Length × width × height gives the tank's total internal volume, but substrate, rocks, driftwood, and equipment like filters and heaters all displace water once they're in the tank — and most tanks aren't filled completely to the rim in practice. A common rule of thumb is to expect 10–20% less usable water volume than the gross figure once a tank is fully set up and stocked.
Frequently asked questions
Why does actual water volume differ from the tank's stated size?
Substrate, decorations, equipment, and not filling completely to the rim all reduce actual water volume below the tank's nominal dimensions — useful to know for accurately dosing medication or water treatments by volume.