An aquarium volume calculator for a hexagon tank converts inner length, width, and water height to litres, US gallons, and UK gallons. Substrate litres use the footprint times gravel depth. Glass thickness is not subtracted; measure inside.
Regular hexagon volume uses (3√3/2) × (side/2 as apothem form via side length as the short diagonal stand-in on this page: (3√3/2)×(L/2)²×H. Measure point-to-point width as length.
Water volume
236.7 L
Results can be wrong. This calculator is unofficial. Figures can be incomplete, rounded, or not updated. Use them at your own risk and check a tape, datasheet, ball band, or official chart before cutting, mixing, buying, or publishing. Measure inside the glass. Hexagon length is point-to-point; a flat-to-flat measure will mis-size the tank. Bowfront extra is an ellipse, not the real curve. Limits of liability are in the terms of service.
Inner. Outer millimetres include glass thickness and overstate water.
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Publisher notes · reviewed 29 October 2026
Point-to-point width is the length field. Area uses (3√3/2)×(L/2)² times height.
If sides are not equal, this over- or under-states. Measure as a rectangle of inscribed dimensions instead.
Hex width as length
Regular hex prism litres = area × height / 1000.
