Tank Volume Calculator
Calculate volume, surface area, and water weight across common aquarium shapes.
Volume (Liters)
64.8
Volume (US gal)
17.12
Surface Area (cm2)
1800
Water Weight (kg)
64.8
Approx. 17.12 US gallons of water
Related Guide
Measure inside dimensions when possible, not outer glass dimensions. Inside dimensions give a closer estimate of real water capacity.
For irregular tanks, split the footprint into simple shapes that do not overlap and sum their volumes. This is exactly how the L-shape calculation works here: enter the short section as the part that sticks out past the long one, measured from the inner corner. Measuring both arms end to end counts the shared corner twice.
For stocking and equipment planning, use the estimated usable volume, which is typically 80-90% of theoretical volume.
FAQ
Should I calculate with full tank height?
For practical use, subtract a few centimeters for the waterline and equipment displacement.
Why does real water volume differ from label volume?
Glass thickness, substrate, hardscape, and equipment reduce usable water volume.
Is bow-front calculation exact?
A bow depth of 0 means a flat front, so the result is exactly the plain rectangle. Enter a bow depth and the bulge is modeled as a half-ellipse, scaling with how far the front curves out relative to tank width — still planning-grade, not engineering precision, since the real curve varies by manufacturer.
How do I measure an L-shape tank?
Split the footprint into two rectangles that do not overlap, then measure each one. The long section is the full arm; the short section is only the part sticking out past it, measured from the inner corner — not the full outer edge. Measuring both arms end to end counts the corner twice and overstates the volume. Both sections are assumed to share one width and one height.
How is water weight estimated?
Freshwater is approximated at 1 kilogram per liter.
Can I use US units only?
Yes. Switch to US units and enter inches. Results still show both liters and US gallons. Gallons here are US liquid gallons (3.785 L), not Imperial gallons (4.546 L).
Did this answer your question?
Hexagonal volume assumes a regular hexagon. Bow-front uses an approximation. L-shape assumes two non-overlapping sections of equal width. Water weight is at freshwater density (~1 kg/L). Results are estimates based on general guidelines. Individual species may have specific requirements.