Aquarium Volume and Weight Calculator (Litres, Gallons and Full Weight)
How much water an aquarium really holds once the glass and the gap at the top are taken out, and how much the full tank weighs with glass, substrate and decor.
Results
What this tool does
A tank's catalogue size is its outside volume: the glass takes up room at the sides and bottom, you never fill to the rim, and gravel and rock displace water, so a tank sold as 200 L often holds closer to 160. The full weight is the water at 1 kg per litre plus the glass (about 2.5 kg per litre of glass) plus substrate and decor, and it is mostly the water — which is why the figure matters for the cabinet and the floor. A 100 × 40 × 50 cm tank weighs around 200 kg when filled, spread over just 0.4 m²; check the stand and, on upper floors, the structure.
Formula
water = (L − 2t)(W − 2t)(depth of water) ÷ 1000 L · glass = (outer box − inner cavity) × 2.5 g/cm³ · total = water + glass + substrate
Variables
| Symbol | Meaning | Unit |
|---|---|---|
l | Outside length of the tank | cm |
w | Outside width of the tank | cm |
h | Outside height of the tank | cm |
gt | Glass thickness | mm |
fb | Gap between the water and the top rim | cm |
dp | Share of the water space taken by substrate and decor | % |
sk | Weight of substrate, rocks and decor | kg |
V | Water the tank really holds | L |
GAL | The same in US gallons | gal |
GW | Weight of the glass | kg |
TW | Weight of the full tank | kg |
FL | Load on the floor under the tank | kg/m² |
Worked example
- Outside length of the tank100 cm
- Outside width of the tank40 cm
- Outside height of the tank50 cm
- Glass thickness8 mm
- Gap between the water and the top rim3 cm
- Share of the water space taken by substrate and decor10 %
- Weight of substrate, rocks and decor15 kg
- Water the tank really holds157.1 L
- The same in US gallons41.5 gal
- Weight of the glass35.2 kg
- Weight of the full tank207 kg
- Load on the floor under the tank518 kg/m²
Limitations
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- Density changes with temperature, moisture and composition. Use a value from the supplier's data sheet whenever precision matters.