Aquarium Glass Thickness Calculator

Calculate safety factors, bowing risk, and panel dimensions for DIY tanks.

1. Tank Shape & Dimensions

*Standard engineering formulas for safety factors are currently calibrated for rectangular flat-panel tanks. Curved glass requires specialized structural analysis.

in
in
in

2. Material & Bracing

6 mm

Standard tanks: 4-8mm. High-end/Large: 10-15mm+.

1.5 mm

Typical gaps range from 1mm to 2mm depending on tank size and silicone brand.

Checking this will automatically subtract material thickness for internal pressure calculations.

Engineering Tip: For any tank over 24" (60cm) high, bracing is strongly recommended to prevent long-term seal fatigue from bowing.

3. Build Style & Overlap

*The cutting list will automatically adjust panel sizes and heights based on material thickness and assembly style.

Results

Safety Factor
6.04 Safety Factor
(≈0.00–0.01 in bow)
Status: Conservative Default (3.8+)
Calculated factor exceeds 3.8 benchmark.
Bowing Risk:Negligible
*Real-world bow varies with build quality, stand flatness, and seam thickness.
Panel Cutting List
Front & Back (x2)35.500 x 15.750 in
Sides (x2)16.938 x 15.750 in
Bottom (x1)34.938 x 16.938 in

*Typical glass shop tolerance: ±0.5–1.0 mm (varies). Confirm with your shop.

*Dimensions assume custom build style. Adjust for tolerances.

Verify results before use. See our disclaimer.

What's Next?

Complete your aquarium setup with these helpful calculators:

⚖️

Weight Calculator →

Check the total weight once your panels are assembled

💧

Volume Calculator →

Determine your exact capacity for the new build

Why Calculate Glass Safety?

Building your own aquarium is rewarding, but water pressure is relentless. A "safety factor" is an engineering estimate of the ratio between a material's strength and the stress applied to it.

A factor of 3.8 is a commonly used conservative default in DIY calculators; many builders go higher for large or rimless tanks to account for material fatigue and minor imperfections.

Understanding Bracing

Bracing allows you to use thinner glass safely. Euro-bracing (strips along the perimeter) or a Center Brace significantly reduce how much the glass bows at the center.

Note: Rimless tanks require the thickest glass to maintain safety.

How to Measure Your Aquarium

How to measure aquarium dimensions - diagram showing length (X axis left to right), width (Y axis front to back), and height (Z axis bottom to top) with measuring tape and arrows indicating each dimension on a planted aquarium tank

What You Need

  • Measuring tape or ruler
  • Paper and pen to write down measurements

Why Accurate Measurements Matter

Knowing your exact tank dimensions is essential for calculating water volume, which affects:

  • Medication and treatment dosing
  • Fertilizer amounts for planted tanks
  • Substrate and gravel quantities
  • Fish stocking capacity and bioload
  • Filter and heater sizing

Common Mistakes to Avoid

Measuring the outside: Prefer inside measurements. If you only have outside measurements, enable "I am measuring from the outside" so we convert to internal water dimensions.

Including decorations: Remove large rocks or driftwood that displace significant water volume.

Mixing units: Do not switch between inches and centimeters mid measurement.

Measuring to the top: Tanks are never filled to the brim. Measure actual water height, not glass height.

Different Tank Types

Bowfront tanks: Measure the straight back panel. The calculator accounts for the curved front.

Cylinder tanks: Measure the diameter (straight line across the widest part) and height.

Corner tanks: Measure the longest straight edges on each side.

Measuring Steps

1. Length

Measure from left to right along the front of the tank. This is the longest side when looking at the tank from the front.

2. Width

Measure from front to back. This is the depth of the tank, how far it extends away from you.

3. Height

Measure from bottom to top on the inside of the tank. Do not include the frame or lid.

Quick Reference

Standard notation:

Length × Width × Height

Example: 36 × 18 × 16 inches

Tools That Work Best

  • Metal measuring tape (most accurate)
  • Cloth tape for curved tanks
  • Ruler for small tanks under 10 gallons
  • Smartphone apps with AR measurement

Important Tips

  • Measure inside the glass: Do not include the frame thickness. Measure the actual water holding area.
  • Measure in inches or centimeters: Most tape measures show both. Pick one unit and stick with it for all three measurements.
  • Round to the nearest whole number: You do not need perfect precision. Rounding to the nearest inch or centimeter is fine.
  • Write it down: Length × Width × Height. For example: 36 × 18 × 16 inches.
Pro tip: If your tank has a center brace or rim, measure from the inside edges where the water actually sits, not the outer frame.

Aquarium Engineering & Structural Safety: A Deep Dive

In the world of custom aquarium fabrication, glass thickness is not just a measurement—it is a life-safety specification. When you build an aquarium, you are creating an open tank that must withstand continuous hydrostatic loading for decades. Understanding the physics behind glass safety is the difference between a thriving aquatic ecosystem and a catastrophic structural failure in your home.

The 3.8 Safety Factor: A Common Benchmark

The frequently cited safety factor of 3.8 is a commonly used DIY benchmark in popular calculators; many builders target higher margins for rimless or large tanks to account for material fatigue and minor glass imperfections. Glass can be subject to material fatigue over time. Builders often aim for this factor to account for variables such as surface scratches, material quality, and potential dynamic loads.

Bowing, Deflection, and Seal Integrity

A panel might be structurally sound, but excessive bowing (deflection) puts the silicone seals under significant shear and peel stress. Unlike standard structural bonds, aquarium joints must resist constant hydrostatic pressure that tries to "peel" the glass away from the silicone bead. In many DIY communities, a common heuristic suggests that if bowing is clearly noticeable to the eye, structural bracing should be considered to reduce long-term fatigue on the primary structural seals.

Material Science: Glass vs. Acrylic

The choice between glass and acrylic involves a trade-off between strength and rigidity. Acrylic has a much higher tensile strength and impact resistance than glass, meaning it is harder to actually "shatter." However, acrylic has a much lower Young’s modulus, meaning it is far less rigid. An acrylic tank will bow significantly more than a glass tank of the same thickness. Because of this, acrylic tanks almost always require a full perimeter top brace (euro-brace) to maintain their shape and prevent the "funhouse mirror" effect of curved panels.

The Impact of Tank Height

It is a common misconception that total volume determines glass thickness. In reality, height is the primary driver of glass stress. Water pressure increases linearly with depth. Because the stress on a panel scales nonlinearly with the depth of the water column, required glass thickness increases rapidly as height grows. A 100-gallon tank that is 4 feet long and 1 foot high requires much thinner glass than a 100-gallon tank that is 2 feet long and 2 feet high.