Aquarium Glass Thickness Calculator
Find the minimum safe glass thickness for each panel of a rectangular aquarium. Enter the tank dimensions, glass type (annealed or tempered) and safety factor to get thickness requirements for the front, sides and bottom.
cm
cm
cm
Glass type
Minimum standard commercial thickness — round up to this when ordering glass
10 mm
glass- 1
Hydrostatic pressure (Pa)
1000 × 9.81 × 0.5 = 4,905Maximum pressure at tank base: water density × g × depth. - 2
Plate bending factor k
0.55Dimensionless coefficient interpolated from Roark Table 11.4 for the controlling panel aspect ratio (b/a). - 3
Required panel thickness (mm)
500 × √(0.55 × 4,905 × 3.8 ÷ 28,000,000) = 9.6 - 4
Recommended standard size
10Next commercial glass thickness (mm) at or above the calculated requirement.
How does this calculator work?
Required glass thickness t = a × √(k × P × SF / σ_MOR), where P = ρgH is max hydrostatic pressure, a is the panel's short side, k is the Roark plate factor (≈ 0.29–0.75 by aspect ratio), SF is the safety factor (3.8 standard) and σ_MOR is glass modulus of rupture (28 MPa annealed, 100 MPa tempered). Round up to the nearest standard size.
Formula
How this is calculated
Water exerts hydrostatic pressure on every submerged surface. At the base of an aquarium the pressure is P = ρ × g × H (density × gravity × depth), which reaches about 4.9 kPa (0.71 PSI) at 50 cm depth. Each glass panel is a plate supported on four edges that must resist this bending load without fracturing.
The calculator uses classical plate-bending theory (Roark's Formulas for Stress and Strain, Table 11.4). The maximum bending stress in a simply-supported rectangular plate under uniform pressure is σ = k × P × a² / t², where k is a dimensionless coefficient that depends on the panel's aspect ratio (longer side ÷ shorter side), a is the shorter panel dimension and t is the glass thickness. Setting σ equal to the allowable stress and solving gives t = a × √(k × P × SF / σ_MOR). Annealed float glass has a modulus of rupture of roughly 28 MPa; tempered glass is about 100 MPa. The safety factor (typically 3.8 for aquariums) guards against material variability, impact, thermal stress and imperfect edge conditions.
The formula uses the maximum hydrostatic pressure (at the base) as if it were uniform over the whole panel — this overestimates the true load and is deliberately conservative. Results are rounded up to the nearest standard commercial glass thickness. Always verify with a qualified glazier for large or high-value installations; silicone joint design is equally important and not covered here.
Frequently asked questions
A safety factor of 3.8 is the industry-standard figure recommended by major aquarium manufacturers and engineering references for hobby fish tanks. It accounts for edge chips, minor surface scratches, silicone joint imperfections and long-term stress relaxation. Higher factors (5+) are sometimes used for public aquariums and reef tanks.
Tempered glass is about 3.5× stronger than annealed, which allows thinner panels. However, if tempered glass breaks it shatters into small fragments, which can injure fish and is very difficult to clean up. Annealed glass breaks in larger shards and is easier to cut to size. Most commercial aquariums use annealed glass with adequate thickness; tempered is common in large display tanks and modern rimless designs.
No. The glass panel calculation assumes the panels are adequately bonded by the silicone seam. Silicone joint design — bead width, depth, cure time and compatibility — is equally critical and must be checked separately, particularly for tanks over 60 cm in any dimension. Consult an aquarium manufacturer or structural glazier for complete tank design.
Also known as
TG we-Calculate Editorial Team. (2026). Aquarium Glass Thickness Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/aquarium-glass-thickness-calculator
TG we-Calculate Editorial Team. "Aquarium Glass Thickness Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/aquarium-glass-thickness-calculator.
TG we-Calculate Editorial Team, "Aquarium Glass Thickness Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/aquarium-glass-thickness-calculator
@misc{wecalculate_aquarium_glass_thickness_calculator, title = {Aquarium Glass Thickness Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/aquarium-glass-thickness-calculator}}, year = {2026}, note = {TG we-Calculate} }
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