Aquarium Volume Calculator by Shape

Start by looking at your tank from above. If the footprint is a simple rectangle or square, use the Rectangular or Cube calculator. Breeder and Shallow tanks are also rectangles distinguished only by their width-to-height proportions: breeders are wider than they are tall, while shallow tanks have a height under 12 inches.

If any panel is curved, identify how much of the tank is round. A fully round cross-section means a Cylinder calculator. A flat back with a curved front is a Half Cylinder (D-shape) or a Bow Front. If the curve wraps into a 90-degree corner, use the Corner Cylinder or Corner Bow Front calculator. Tanks with two rounded ends (pill-shaped) use the Round End calculator, while a single rounded end is a Bullnose.

Polygon tanks have multiple flat panels of equal length. Count the sides: five panels is a Pentagon, six is a Hexagon, and eight is an Octagon. If one panel sits flat against a wall while the others angle outward, you likely have a Flat Back Hexagon. Tanks that taper from a wide front to a narrow back are Trapezoids.

For tanks with an unusual footprint, the L-Shaped calculator handles two joined rectangular sections, and the Corner Prism calculator covers right-triangle tanks that fit into room corners. If your tank does not match any of these shapes, try breaking it into simpler components and calculating each section individually. If your tank is under 10 gallons, the nano aquarium volume guide lists common dimensions and actual water volumes for pico, cube, shallow, and standard nano formats.