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Fish Tank Volume Calculator

Aquarium Glass Thickness Calculator

Recommended minimum thickness

10 mm

≈ 0.39 inch · safety factor 3.8

This is a guideline based on standard safe-thickness charts. A braced top (centre brace or full rim) lets you use thinner glass. For tanks taller than 60 cm or longer than 150 cm, have the design checked by a professional and consider tempered glass.

Find the recommended minimum glass thickness for your aquarium. Enter the water height, tank length and glass type to get a safe thickness in millimetres, based on standard safety charts.

How to choose aquarium glass thickness

Glass thickness depends mostly on water height, because water pressure rises with depth, and on the unsupported length of the panel. Standard charts use a safety factor of about 3.8 for regular float glass and about 7.6 for tempered glass. A braced top lets you use thinner glass, while taller or longer tanks need thicker glass. For tanks over 60 cm tall, have the design checked by a professional.

Minimum glass thickness by water height

Water height (cm)Float glass, length up to 120 cm (mm)Float glass, length over 120 cm (mm)Tempered glass, length up to 120 cm (mm)
25666
30886
4010108
50121510
60151912
70191915

Calculated with the same formula as the calculator above. Values are rounded.

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Frequently asked questions

How thick should aquarium glass be?
It depends on water height. As a guide, up to 35 cm needs about 8 mm, up to 45 cm about 10 mm, and up to 55 cm about 12 mm of regular float glass.
Does tank length affect glass thickness?
Yes. Longer unsupported panels bow more, so a long tank may need a step thicker glass or a top brace.
What safety factor is used for aquarium glass?
About 3.8 for regular float glass and about 7.6 for tempered glass, meaning the glass is designed to fail well above the working load.
Is tempered glass better for aquariums?
Tempered glass is much stronger for the same thickness, but it cannot be drilled or cut after it is tempered.
Does a top brace let me use thinner glass?
Yes. A centre brace or full rim reduces how much the glass bows, so a braced tank can use thinner glass than an open-top one.
When should I consult a professional?
For tanks taller than 60 cm or longer than 150 cm, or any large custom build, have the glass thickness verified by a professional.

Related guides

Learn the core ideas behind fish tank volume before or after using the calculator.