Aquarium Volume Calculator
This aquarium volume calculator shows how much water really fits in your tank: enter outer size, glass thickness, water level and substrate, then read gallons, liters and the total weight for the stand.
Source: Wikipedia – Aquarium (volume, weight of water and glass, stability). Updated: .
How it is calculated
A 36 × 18 × 16 in tank holds about 45 US gallons gross; with 6 mm glass, 1 in of freeboard, 2 in of substrate and 10 % decor, about 31 gallons (117 liters) of water remain and the total weighs roughly 330 lb. The calculator shows how much water actually stands in the tank.
How it is calculated
Gross volume is length times width times height of the outer dimensions. For the real water volume the inner dimensions are used, outer size minus twice the glass thickness, and the water height without the bottom glass and freeboard. The volume of the substrate, which displaces water, is deducted, plus a share for rocks and wood. One liter of water weighs one kilogram; substrate is multiplied by its bulk density, which you can adjust.
Why the calculation matters
- The liter figure in shops often means gross volume. Less water actually fits.
- For water care, dosing and equipment the real water volume counts.
- The total weight decides whether the stand and floor can carry the tank.
More calculators: the pond liner calculator, the volume converter and the weight converter.
Frequently asked questions
How do I calculate the gallons of an aquarium?
Length times width times height in inches divided by 231 gives US gallons gross. For the real water use inner dimensions and subtract substrate and decor. The calculator does that.
Why does my aquarium hold less than advertised?
Because glass thickness, the water level below the rim, substrate and decor take up space. The advertised figure is usually the gross volume.
How heavy is a filled aquarium?
Count about one kilogram per liter of water (8.3 lb per US gallon) plus substrate, glass and equipment. The calculator lists water and substrate; glass comes on top.
What is the bulk density of substrate?
Sand and gravel are often 1.5 to 1.7 kg per liter, planted soil often lower. The value is adjustable in the calculator.
Sources and legal basis
- Wikipedia – Aquarium (volume, weight of water and glass, stability)
- NIST – conversion between US gallon and liter (1 gal = 3.785411784 l, 1 lb = 0.45359237 kg)
As of: · Editorial policy
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