Calculator Inputs
Example Data Table
| Tank Size | Water Height | Support Type | Safety Factor | Use Case |
|---|---|---|---|---|
| 36 × 18 × 20 in | 18 in | Euro braced | 3.5 | Small reef display |
| 48 × 24 × 24 in | 22 in | Rimless | 3.8 | Medium display tank |
| 72 × 30 × 30 in | 28 in | Cross braced | 4.2 | Large custom aquarium |
Formula Used
The calculator uses hydrostatic pressure, stress control, and deflection control. It compares each panel and returns the largest practical value.
Pressure: P = density × gravity × water height.
Stress thickness: t = span × square root of coefficient × pressure ÷ allowable stress.
Deflection thickness: t = cube root of coefficient × pressure × span⁴ ÷ modulus × allowed deflection.
Allowed stress: acrylic strength ÷ safety factor.
The final recommendation adds joint allowance and extra margin. This helps cover fabrication tolerance, polishing loss, and real shop variation.
How To Use This Calculator
Enter the inside length, width, height, and actual water height. Select the unit used for those dimensions. Choose the support condition that best matches the planned build. Enter acrylic strength, elastic modulus, and safety factor. Use higher safety factors for public tanks, tall tanks, warm water, or uncertain sheet quality. Press the calculate button. The result appears above the form and below the header. Use the CSV or PDF buttons to save the report.
Aquarium Acrylic Thickness Planning Guide
Why Acrylic Thickness Matters
Acrylic aquariums look clean and bright. They are also lighter than glass. Yet the panels must resist water pressure every hour. A tall tank creates more pressure near the bottom. A long front panel also bends more than a short panel. Thickness is therefore not based on volume alone.
What The Calculator Checks
This tool checks stress and deflection together. Stress relates to material strength. Deflection relates to visible bowing. A panel may be strong enough but still bend too much. That is why the calculator reports both limits. The recommended value uses the larger result.
Support And Bracing
Top support changes the result. A rimless tank needs more stiffness. Euro bracing helps the top edge. Cross bracing adds more restraint. A fully framed build gives the most support. The calculator applies support coefficients to reflect these common design differences.
Safety Factor
Acrylic quality, bonding skill, temperature, scratches, and age affect real strength. A safety factor reduces the allowable stress. A larger factor gives a more cautious answer. Many builders use higher margins for deep tanks and public displays.
Water Load
Water is heavy. One liter weighs about one kilogram with fresh water. Saltwater may be slightly heavier. The calculator lets you change water density. This is useful for marine tanks, brackish tanks, and unusual liquid displays.
Practical Buying Notes
Always round up to the nearest available sheet size. Do not round down. Account for routed edges, polishing, seams, and openings. Thick acrylic also needs proper bonding technique. A beautiful panel can fail if the seam is weak.
Final Design Review
This calculator supports planning. It does not replace professional review. Very large tanks need engineered design. Tall tanks need special attention. Use conservative inputs when unsure. Safe acrylic choices protect the tank, livestock, flooring, and nearby equipment.
FAQs
1. What thickness should I choose after calculation?
Choose the recommended thickness or the next thicker available sheet. Do not round down. Extra thickness improves stiffness, seam strength, and long term safety.
2. Does tank height affect acrylic thickness?
Yes. Water pressure rises with water height. Taller tanks usually need thicker acrylic, even when the length and width remain unchanged.
3. Why does rimless support need more thickness?
A rimless top gives the upper edge less restraint. The front and side panels can bow more, so added thickness helps control deflection.
4. Can I use this for saltwater tanks?
Yes. Increase water density if needed. Saltwater is usually slightly heavier than fresh water, which can raise pressure and load estimates.
5. What is a safe safety factor?
Many planning cases use values around 3 to 4. Use higher values for tall tanks, public displays, uncertain materials, or critical installations.
6. Does this replace a professional design?
No. It gives planning estimates only. Large, tall, custom, or commercial aquariums should be reviewed by an experienced builder or engineer.
7. Why compare stress and deflection?
A panel can resist breaking but still bow too much. Comparing both checks gives a more practical acrylic thickness recommendation.
8. Should I include freeboard in water height?
Use actual operating water height, not total outside height. If the tank may overfill, use a higher water height for safer planning.