Common metric aquarium sizes
| Tank | Dimensions (cm) | Gross volume |
|---|---|---|
| 60 cm | 60 × 30 × 30 | 54 L |
| 80 cm | 80 × 30 × 35 | 84 L |
| 90 cm | 90 × 45 × 40 | 162 L |
| 100 cm | 100 × 40 × 50 | 200 L |
| 120 cm | 120 × 45 × 50 | 270 L |
| 150 cm | 150 × 60 × 60 | 540 L |
Why tanks hold less than the label
The gallon rating is a rounded figure from the outside dimensions. The glass takes up room, nobody fills to the very top, and gravel and rock displace more. Expect the real water volume of a planted or rock-heavy tank to be 10–20% under its rating. The aquarium volume calculator works it out for your exact setup, and how to measure an aquarium covers taking the measurements.
Choosing between sizes
Footprint matters as much as gallons. The 55 and 75 gallon tanks are both 48 inches long, but the 75 is 18 inches front to back instead of 13, which gives far more room for aquascaping. The 40 breeder holds less water than a 55 but has a bigger floor. Check the filled weight against your stand and floor before you buy; see how much a fish tank weighs.