AQUARIUM CALCULATOR PRO
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Standard Fish Tank Sizes & Dimensions Chart

Explore dimensions, gallon capacities, filled weights, and floor footprints for 26 standard aquarium sizes with instant 1-click calculator sync.

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Quick Answer: Most Popular Aquarium Sizes & Dimensions
The 3 most popular standard home aquarium sizes are: 10 Gallon: 20″L × 10″W × 12″H (filled weight: 111 lbs). 20 Gallon Long: 30″L × 12″W × 12″H (filled weight: 225 lbs). 55 Gallon: 48″L × 13″W × 21″H (filled weight: 625 lbs). Total filled aquarium weight averages 10–12 lbs per gallon including glass, water, and substrate.
Tank Model & TypeDimensions (L × W × H)VolumeEmpty WtFilled WtSurface AreaMin GlassActions
2.5 Gallon Pico
12″ × 6″ × 8″2.5 Gal3 lbs27 lbs72 sq in3 mm
5 Gallon Standard
16″ × 8″ × 10″5 Gal7 lbs55 lbs128 sq in4 mm
10 Gallon Standard
20″ × 10″ × 12″10 Gal11 lbs111 lbs200 sq in4 mm
15 Gallon Standard
24″ × 12″ × 12″15 Gal21 lbs170 lbs288 sq in5 mm
20 Gallon High
24″ × 12″ × 16″20 Gal25 lbs225 lbs288 sq in5 mm
20 Gallon Long
30″ × 12″ × 12″20 Gal25 lbs225 lbs360 sq in5 mm
29 Gallon Standard
30″ × 12″ × 18″29 Gal40 lbs330 lbs360 sq in6 mm
30 Gallon Breeder
Breeder
36″ × 18″ × 12″30 Gal48 lbs348 lbs648 sq in6 mm
37 Gallon Column
Cube
30″ × 12″ × 22″37 Gal45 lbs415 lbs360 sq in6 mm
40 Gallon Breeder
Breeder
36″ × 18″ × 16″40 Gal58 lbs458 lbs648 sq in6 mm
40 Gallon Long
48″ × 13″ × 16″40 Gal55 lbs455 lbs624 sq in6 mm
50 Gallon Standard
36″ × 18″ × 19″50 Gal80 lbs580 lbs648 sq in8 mm
55 Gallon Standard
48″ × 13″ × 21″55 Gal78 lbs625 lbs624 sq in8 mm
65 Gallon High
Breeder
36″ × 18″ × 24″65 Gal112 lbs762 lbs648 sq in10 mm
75 Gallon Standard
48″ × 18″ × 21″75 Gal140 lbs850 lbs864 sq in10 mm
90 Gallon Standard
48″ × 18″ × 24″90 Gal160 lbs1050 lbs864 sq in10 mm
110 Gallon High
48″ × 18″ × 30″110 Gal215 lbs1320 lbs864 sq in12 mm
120 Gallon Wide
Breeder
48″ × 24″ × 24″120 Gal215 lbs1400 lbs1152 sq in12 mm
125 Gallon Long
72″ × 18″ × 21″125 Gal206 lbs1400 lbs1296 sq in12 mm
150 Gallon Standard
72″ × 18″ × 28″150 Gal290 lbs1750 lbs1296 sq in12 mm
180 Gallon Monster
72″ × 24″ × 24″180 Gal338 lbs2100 lbs1728 sq in15 mm
14 Gallon Cube
Cube
15″ × 15″ × 15″14.6 Gal22 lbs160 lbs225 sq in5 mm
UNS 45U / ADA 45P
Rimless
17.7″ × 11″ × 11″9.3 Gal16 lbs105 lbs194.7 sq in5 mm
UNS 60U / ADA 60P
Rimless
23.6″ × 14.2″ × 14.2″20.6 Gal32 lbs225 lbs335.12 sq in6 mm
UNS 90U / ADA 90P
Rimless
35.4″ × 17.7″ × 17.7″48 Gal85 lbs525 lbs626.5799999999999 sq in10 mm
36 Gallon Bowfront
30″ × 15″ × 21″36 Gal54 lbs414 lbs450 sq in6 mm

Aquarium Dimensions Guide: Footprint vs. Height Analysis.

Choosing the right aquarium size involves far more than gross gallons. Tank footprint determines surface area for oxygenation and bottom-dweller territory, while height dictates required glass thickness and light penetration.

40 Gallon Breeder vs. 55 Gallon

Although the 55G holds 15 more gallons, it is notoriously narrow (only 13 inches wide). The 40 Gallon Breeder (36″ × 18″ × 16″) provides 648 sq. inches of floor footprint compared to the 55G's 624 sq. inches. Its 18-inch front-to-back depth gives superior aquascaping perspective, better water-to-air gas exchange, and easier maintenance since you don't need to reach 21 inches deep.

20 Gallon Long vs. 20 Gallon High

A 20 Gallon Long (30″ × 12″ × 12″) provides 360 sq. inches of footprint and a 30-inch horizontal swimming runway — perfect for schooling tetras, danios, and rasboras. A 20 Gallon High (24″ × 12″ × 16″) has only 288 sq. inches of surface area but offers vertical room for tall plants (Amazon Swords) and deep-bodied fish like Angelfish pairs.

Rimless ADA & UNS Standards

Modern aquascaping follows standard metric dimensions pioneered by Takashi Amano (ADA). The 60P (60 × 30 × 36 cm / 17.1 gal) and 90P (90 × 45 × 45 cm / 48 gal) are engineered with golden ratio proportions and require 6 mm to 10 mm low-iron float glass with high-tensile clear silicone to eliminate distortion without plastic braces.

How to Calculate Filled Weight & Floor Support

Pure water weighs 8.34 lbs per US gallon (1 kg per litre). When including the glass tank, gravel/sand bed (1.5 lbs/gal), and rock hardscape, a filled aquarium weighs approximately 10 to 12 pounds per gallon (1.2 to 1.4 kg/L). For aquariums exceeding 55 gallons (>600 lbs), always place the stand perpendicular across multiple floor joists against an exterior load-bearing wall.

Knowledge Base

Frequently Asked Questions

Expert answers to detailed planning questions for this calculator module.

Aquarium Sizes & Dimensions

What are the dimensions of a standard 55-gallon fish tank?

A standard 55-gallon aquarium measures 48 inches long by 13 inches wide by 21 inches tall (122 × 33 × 53 cm). Because it is narrow (13 inches deep), it is best suited for fast-swimming schooling fish, but offers limited floor depth for intricate aquascaping compared to a 40-gallon breeder or 75-gallon tank.

Why is a 40-gallon breeder considered better than a 55-gallon tank?

The 40-gallon breeder measures 36″ L × 18″ W × 16″ H. Its 18-inch front-to-back depth provides 50% more floor footprint area than a 55-gallon tank (13 inches wide). This wide footprint allows for dramatic aquascaping depth, superior water-to-air oxygenation, and much more territory for bottom-dwelling fish like cichlids, corydoras, and plecos.

What is the difference between a 20-gallon long and a 20-gallon high aquarium?

A 20-gallon long measures 30″ L × 12″ W × 12″ H, while a 20-gallon high measures 24″ L × 12″ W × 16″ H. The 20-gallon long is preferred by most experienced aquarists because its 30-inch length provides 25% more swimming runway and greater surface area for gas exchange, making it ideal for active schooling tetras and rasboras.

How much does a 75-gallon fish tank weigh when filled?

A 75-gallon aquarium weighs approximately 140 lbs (64 kg) empty. When filled with 75 gallons of water (625 lbs), 80 lbs of substrate, and decorations, the total operational weight reaches 850 to 900 lbs (385 to 410 kg). Verify that your stand and floor joists can handle this concentrated load.

What are standard rimless aquarium sizes (ADA sizing)?

Standard rimless sizes follow the Japanese/European dimensions: 45P (45×27×30 cm, 9.6 gal), 60P (60×30×36 cm, 17.1 gal), 90P (90×45×45 cm, 48 gal), and 120P (120×45×45 cm, 64 gal). They feature ultra-clear low-iron glass, clear silicone, and slightly thicker panels (6–12 mm) to withstand water pressure without plastic framing.