Aquarium volume calculator

Calculate the exact capacity of your tank. Essential for dosing medicine, adding water conditioner, and stocking fish.

20
US Gallons

Equivalent to 75.7 liters.

The "Glass Displacement" reality

I genuinely hate it when a tank is sold as "20 Gallons" but it only holds about 17. Why? Because you’ve got 2 inches of substrate at the bottom, a giant piece of driftwood in the middle, and you never fill it all the way to the rim. This calculator gives you the **theoretical maximum**, but when you’re dosing medicine or chemicals, always subtract about 15-20% for the actual water volume.

Note on Bow Fronts: Bow front tanks are notoriously tricky because the volume isn't just L x W x H. We use a parabolic formula here to estimate that extra "bulge." It’s much more accurate than the generic "rectangle plus a bit" method most people use.