Aquarium Dimensions

Aquarium Calculator

This is for dimensions with centimeters







This is for dimensions with inches






How much water will the tank size really hold?

Theoretical volume

This is the absolute volume when an otherwise empty tank is filled to the very top edge with water.  This is the size that the manufacturer will often state for the aquarium sizes.

Realistic volume

Allows for decor displacement and that the tank won’t be filled to the very top edge. As such this is a far more accurate measurement to use.

How high you fill the water and what you place in the tank will decrease the amount of water volume to a more realistic lower quantity. 

For example, a small 2.5 Gallon tank 12 x 6 x 8 holds 2.5 Gallons when completely full to the top.  But allowing for the water to be lower than the very top rim, some plants and decorations in the tank the actual realistic volume is more likely to be 2.25 Gallons.   Fish tank sizes are easy to calculate using our calculator, just be careful when working out how much water for dosing with any chemicals for pH and GH levels, or sizing filters etc.

When YOU calculate the water volume in the calculator YOU should reduce the HEIGHT as you are not really going to fill it with water to the very top.

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Aquarium Weight

Below is an estimate of aquarium weights comparing empty to full, freshwater or saltwater. 

The weights are an estimate because the amount of rock, planting, thickness of glass are assumed figures.
For planting and rocks, this includes any decor, but not fish, so that you can see what we have assumed.

A gallon of freshwater at 39.2ºF, or 4ºC and a specific gravity of 1.000 weighs 8.3454 lbs.

The weight of the water will increase directly proportionate to the weight of the salt being dissolved in the water. 
1 gallon of water 8.3454 lbs times the specific gravity of say 1.025 equals 8.5540 lbs (8.3454 x 1.025 = 8.5540).

1 gallon of saltwater at 1.025 specific gravity equals 8.554 lbs.

For more information on water weight see our post ‘How much does a gallon of water weigh?’

For your own tank you decide how much planting etc will be added and alter the weights to suit your needs.

 

SMALL-SIZED AQUARIUMS
Tank Size L x W x H Empty Weight Plants & Rocks Filled Weight Freshwater (Including Plants & Rocks) Filled Weight Saltwater (Including Plants & Rocks)
  Inches lbs lbs lbs lbs
2 1/2 gallon 12″ x 6″ x 8″ 3 3 26.9 27.4
5 gallon 16″ x 8″ x 10″ 7 10 58.7 59.8
10 gallon “Leader” 20″ x 10″ x 12″ 11 15 109.5 111.5
15 gallon 24″ x 12″ x 12″ 21 25 171.2 174.3
15 gallon High 20″ x 10″ x 18″ 22 25 172.2 175.3
           
MID-SIZED AQUARIUMS
Tank Size L x W x H Empty Weight Plants & Rocks Filled Weight Freshwater (Including Plants & Rocks) Filled Weight Saltwater (Including Plants & Rocks)
  Inches lbs lbs lbs lbs
20 gallon High 24″ x 12″ x 16″ 25 30 221.9 226.1
20 gallon Long 30″ x 12″ x 12″ 25 30 221.9 226.1
25 gallon 24″ x 12″ x 20″ 32 40 280.6 285.9
29 gallon 30″ x 12″ x 18″ 40 45 327 333.1
30 gallon Breeder 36″ x 18″ x 12″ 48 48 346.4 352.6
40 gallon Breeder 36″ x 18″ x 16″ 58 60 451.8 460.2
40 gallon Long 48″ x 12″ x 16″ 55 60 448.8 457.2
           
LARGE AQUARIUMS
Tank Size L x W x H Empty Weight Plants & Rocks Filled Weight Freshwater (Including Plants & Rocks) Filled Weight Saltwater (Including Plants & Rocks)
  Inches lbs lbs lbs lbs
50 gallon 36″ x 18″ x 19″ 100 70 587.3 597.7
55 gallon 48″ x 13″ x 21″ 107 75 641 652.5
65 gallon 36″ x 18″ x 24″ 126 90 758.5 772
75 gallon 48″ x 18″ x 21″ 140 110 875.9 891.6
90 gallon 48″ x 18″ x 24″ 160 120 1031.1 1049.9
125 gallon 72″ x 18″ x 21″ 206 130 1379.2 1405.3
150 gallon 72″ x 18″ x 28″ 338 140 1729.8 1761.1
180 Gallon 72″ x 24″ x 25″ 350 170 2022.2 2059.7
225 Gallon 72″ x 27.5″ x 27.5″ 360 190 2427.7 2474.7

 

Please download Our ‘Aquarium Dimensions, Sizes & Weights’ booklet for your future reference:

Aquarium Dimensions Booklet
Aquarium Dimensions PDF Booklet