Aquarium Glass Thickness Calculator
Engineering Explained Simply
Choosing the right glass thickness for a custom aquarium is one of the most structurally critical decisions in the build process. Too thin and the panels bow excessively, stress the silicone seals over time, or fail catastrophically. Too thick and you add unnecessary weight and cost. The correct thickness depends on three primary factors: the height of the water column, the span of each panel, and the type of bracing used. A 60 centimetre tall tank exerts more than double the stress on its glass compared to a 30 centimetre tall tank of the same volume, because water pressure increases with depth and the bending stress on the panel increases faster than the height alone.
This aquarium glass thickness calculator covers all seven standard panel thicknesses from 5 mm through to 19 mm, and supports three materials — standard float glass, tempered glass, and cast acrylic. The structural safety factor slider lets you set your target from 2.5 (the absolute minimum) through to 6.0 (very conservative), with 3.8 being the widely accepted industry standard for DIY aquarium builds. Four bracing styles are available: rimless with no brace, euro-bracing with perimeter strips, a centre cross-brace, and full frame combining both. Each bracing style changes how the calculator treats the effective panel span and height, reflecting the genuine structural improvement that well-bonded bracing provides.
Calculate the exact glass or acrylic thickness required for your aquarium using real engineering plate-bending formulas—not guesswork. This calculator factors in tank dimensions, bracing styles (rimless, euro-braced, centre brace), and adjustable safety factors to deliver precise, reliable results. It also provides bowing estimates and a complete panel cutting list, making it ideal for both beginner DIY builders, custom tankmakers and advanced aquascapers designing structurally safe tanks.
Free-to-use. No signup required.
The seven clickable thickness presets — 5, 6, 8, 10, 12, 16, and 19 mm — each show the safety factor they achieve for your specific tank dimensions in real time, colour coded from red through to blue. This lets you immediately see which thickness is adequate, which is borderline, and which gives you a comfortable engineering margin. The minimum required thickness for your target safety factor is calculated and displayed alongside the selected thickness, so you can see exactly how much margin you have chosen.
The panel cutting list at the bottom of the calculator generates exact dimensions for all five panels — front, back, left side, right side, and bottom — in both millimetres and inches. These dimensions account for your chosen glass thickness and the silicone joint gap you specify, and adjust based on whether your assembly style has the front and back panels running the full external length or the side panels running the full external width. Take this cutting list directly to your glass supplier.
Float glass is suitable for all DIY builds and can be drilled and cut at any time. Tempered glass is three to four times stronger and fails more safely into small rounded pieces, but cannot be cut, drilled, or modified after tempering — all holes for overflows and bulkheads must be specified before the glass is sent for tempering. Cast acrylic is lighter than glass and optically clearer with no green tint, but scratches easily, yellows under ultraviolet light over time, and creeps slowly under sustained load, which is why the calculator uses a conservative long-term strength figure for acrylic rather than its short-term tensile rating.
Always consult a structural engineer or contact us before building tanks over 400 litres or taller than 80 centimetres. These calculations use established engineering principles calibrated against industry practice and do not account for glass defects, silicone application quality, stand flatness, or accidental impact loads.