Aquarium Glass Thickness Calculator

This aquarium glass thickness calculator estimates the minimum safe glass for a tank panel from the panel width, the water depth and a safety factor you choose. Water pressure rises with depth and pushes outwards on the glass, hardest right at the bottom, so the panel that has to be sized is the one holding the deepest water, usually the front or a side. The tool treats that panel as a strip spanning its shorter dimension, simply supported around the edges, and works out the thickness needed to keep the bending stress in the glass below a safe limit. That limit is the breaking stress of glass divided by your safety factor, which is why a bigger safety factor calls for thicker glass. It then rounds up to the next standard glass size, so you get a practical figure you can actually order. This suits hobbyists planning a DIY build, checking a second-hand tank, or sanity-checking a quote, and it deliberately errs on the thick side by ignoring any bracing, which always helps rather than hurts. Enter your panel width and fill depth in millimetres, pick a safety factor, and read the recommended thickness. A worked example and the formula are set out below. For a large, tall or public-facing tank, treat this as a first estimate only and have the design confirmed by a qualified glazier.

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At a safety factor of 3.8, a 900 mm x 450 mm panel needs at least 7.98 mm of glass, so 8 mm is the recommended standard thickness.

Assumes a single flat annealed panel with no bracing, water density 1,000 kg/m3, gravity 9.81 m/s2 and a glass breaking stress of 40 MPa. Bracing and tempering allow thinner glass. Estimate only: have large or tall tanks checked by a professional.