FishMaths

Fish tank size chart

Common aquarium sizes with typical dimensions, liters and water weight. Tap any size for gravel, heater and filter numbers.

TankDimensionsLitersWater weight
5 gallon16 × 8 × 10 in
41 × 20 × 25 cm
18.9 L42 lb
19 kg
10 gallon20 × 10 × 12 in
51 × 25 × 30 cm
37.9 L83 lb
38 kg
20 gallon high24 × 12 × 16 in
61 × 30 × 41 cm
75.7 L167 lb
76 kg
20 gallon long30 × 12 × 12 in
76 × 30 × 30 cm
75.7 L167 lb
76 kg
29 gallon30 × 12 × 18 in
76 × 30 × 46 cm
109.8 L242 lb
110 kg
40 gallon breeder36 × 18 × 16 in
91 × 46 × 41 cm
151.4 L334 lb
151 kg
55 gallon48 × 13 × 21 in
122 × 33 × 53 cm
208.2 L459 lb
208 kg
75 gallon48 × 18 × 21 in
122 × 46 × 53 cm
283.9 L626 lb
284 kg
90 gallon48 × 18 × 24 in
122 × 46 × 61 cm
340.7 L751 lb
341 kg
125 gallon72 × 18 × 21 in
183 × 46 × 53 cm
473.2 L1,042 lb
473 kg

Dimensions are typical outside measurements and vary a little between brands.

How to read this chart

Tanks with the same gallon number can have very different shapes. A 20 long and a 20 high hold the same water, but the long gives fish more swimming room and the high gives plants more height. Footprint (length times depth) decides how much gravel you need and how much room bottom dwellers get.

How do I convert gallons to liters for a fish tank?
Multiply US gallons by 3.785. A 20 gallon tank holds about 75.7 liters and a 55 gallon holds about 208 liters.
How much does a full fish tank weigh?
Water weighs about 8.34 pounds per US gallon. Add glass, substrate and rock, and a full tank usually weighs 10 to 20 percent more than the water alone.