Aquarium volume, glass thickness & weight calculator
Calculate gross and net water volume, estimate water and total weight, and use the result for dosing, water changes and equipment planning.
Quick presets
Measured from outside the glass — the calculator subtracts glass thickness to get the inner cavity.
Estimated common reference, not structural engineering advice. For custom or large tanks, confirm with the manufacturer or a professional builder.
Substrate & decor
Results
Net water volume
50.1 L(13.2 US gal)
Use net water volume for dosing, water treatments and fertilizers.
For large aquariums, old buildings, upper floors, or narrow stand legs, verify floor capacity before filling the tank.
Plan and track this tank in AquaPilot
Save the spec, log equipment, livestock, parameters and maintenance — all linked to one aquarium.
What can this calculator help with?
Sizing a new tank against your stand, your floor and your livestock plan.
Knowing the real (net) water volume before dosing fertilizers, medications or water conditioner.
Estimating how much substrate you need to buy and how heavy it will be.
Checking how much load your floor and stand will see when the tank is full.
Comparing standard tank sizes side by side before you commit.
How it works
- 1
Pick a preset or enter your dimensions
Use a standard-size chip to snap to a common tank, or type your own length, width and height in centimetres.
- 2
Let it pick the glass — or override
By default the calculator suggests a thickness based on tank height. You can override with any value from 4 mm to 19 mm.
- 3
Read the results
Volume in litres and US gallons, the empty-tank weight from the glass panels, water weight, and total filled weight you'll need to support.
When to use it
Buying or building a new tank
Sanity-check the dimensions against your stand, your floor and your livestock plans before placing the order.
Comparing standard sizes
Click through the presets to see how a 90 cm vs 120 cm tank compares on volume, weight and footprint.
Checking floor load
Older buildings, mezzanines or wooden floors can struggle with large tanks. The kg/cm² number is a quick first check.
How the numbers are calculated
Volume is just length × width × height in cm divided by 1,000. Weight is glass density (≈ 2,500 kg/m³) times the surface area of the five panels times their thickness, plus 1 kg per litre of water. Substrate and decor add roughly another 10%.
Glass thickness rule of thumb
A common conservative table based on tank height. Real values depend on length, support and whether the glass is tempered — when in doubt, ask a glass shop or use a dedicated structural calculator.
| Tank height | Suggested thickness |
|---|---|
| ≤ 30 cm | 6 mm |
| 31–40 cm | 8 mm |
| 41–50 cm | 10 mm |
| 51–60 cm | 12 mm |
| 61–70 cm | 15 mm |
| > 70 cm | 19 mm |
Top and cross bracing
Tanks longer than ~80 cm benefit from a top frame and at least one cross brace to keep the long panels from bowing under water pressure. Most rimless tanks rely on tempered glass and Eurobracing for the same reason.
Tempered (safety) glass
Tempered glass is several times stronger than annealed glass and shatters into small chunks instead of large shards. The bottom panel and any tall side panels are good candidates — but you can't drill tempered glass after the fact.
Worked examples
A few standard-size tanks with rough numbers from this calculator.
| Dimensions | Volume | Glass (auto) | Total filled |
|---|---|---|---|
| 60 × 30 × 36 cm | 65 L (17 US gal) | 8 mm | ~85 kg |
| 120 × 40 × 50 cm | 240 L (63 US gal) | 10 mm | ~310 kg |
| 180 × 60 × 60 cm | 648 L (171 US gal) | 12 mm | ~810 kg |
Volumes are gross — actual water volume after substrate, hardscape and the gap below the rim is typically 10–20% lower.
Frequently asked questions
How accurate is this calculator?
Volume is exact for the geometry. Glass and water weight are accurate to within a few percent. The thickness suggestion is a conservative rule of thumb — it doesn't replace an engineering calculation for tall, long, or rimless tanks.
What about tempered glass?
Tempered (safety) glass is roughly 4–5× stronger than ordinary annealed glass, so a tempered panel can sometimes be one step thinner. This calculator assumes annealed glass, which is the safer default.
Do I need cross bracing?
Tanks longer than ~80 cm usually do — a top brace stops the long panels from bowing outward when full. Rimless tanks compensate by using thicker, tempered glass with Eurobracing strips along the top.
Can my floor handle this tank?
The floor load shown here is a rough indicator, not a structural assessment. Smaller aquariums are usually fine, but larger tanks — especially with a heavy stand, substrate, rocks, and water — can put real strain on a floor. What matters isn't just the total weight: it's also how the load is distributed, the type of floor (concrete vs. wooden joists), the placement, and the building's construction. The safest setup keeps heavier tanks close to a load-bearing wall with weight evenly distributed across the stand. For large tanks, older buildings, wooden-joist floors, or any doubts at all, have the placement reviewed by a structural engineer.
Why is the recommended thickness more than what my LFS quoted?
Local fish-store tanks are often built with tempered glass, which lets them go thinner. The rule-of-thumb table here assumes annealed glass and bias toward safety. A reputable tank builder using a dedicated structural calculator will always be more precise.
Now that you know your tank volume:
Water change calculator
Work out the % and litres to change to hit your target parameter.
Fertilizer calculator
Convert salts and solutions into doses for your net water volume.
Substrate calculatorSoon
Plan how much sand, gravel or aquasoil you need by depth.
Heater calculatorSoon
Pick a heater wattage based on tank volume and room temperature.
Filter flow calculatorSoon
Match filter flow rate to tank size and stocking density.
Stocking calculatorSoon
Estimate fish capacity from net volume, filtration and species.
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