Aquarium volume calculator
Enter your tank's shape and dimensions in inches or centimeters. The calculator gives the volume in US gallons and liters and the weight of the water alone. Set how far below the rim the water stands to get the volume you actually fill.
Your tank holds
18.7 US gallons
70.8 liters
The water alone weighs about 156 lb (70.8 kg).
Enter dimensions greater than zero, with the water level below the top of the tank.
Find plants that fit your tankVolume of common tank dimensions
| Dimensions | US gallons | Liters |
|---|---|---|
| 20 × 10 × 12 in | 10.4 | 39.3 |
| 24 × 12 × 16 in | 19.9 | 75.5 |
| 30 × 12 × 12 in | 18.7 | 70.8 |
| 30 × 12 × 18 in | 28.1 | 106 |
| 36 × 18 × 16 in | 44.9 | 170 |
| 48 × 13 × 21 in | 56.7 | 215 |
| 48 × 18 × 21 in | 78.5 | 297 |
| 72 × 18 × 24 in | 135 | 510 |
| 60 × 30 × 36 cm | 17.1 | 64.8 |
| 90 × 45 × 45 cm | 48.1 | 182 |
| 120 × 50 × 50 cm | 79.3 | 300 |
How the volume is calculated
A rectangular tank holds length × width × water depth. A cylinder holds the area of its circle, π × (diameter ÷ 2)², times the depth, and a hexagonal tank with equal sides holds 2.598 × side² times the depth.
Cubic inches become US gallons by dividing by 231, which is how the US gallon is defined. Cubic centimeters become liters by dividing by 1,000. One inch is exactly 2.54 cm.
Why the real number is lower
Measurements taken on the outside of the tank include the glass, so the result is a little more than the tank can hold. Measure inside the glass for a closer figure.
Substrate, rocks and wood take up space that water would otherwise fill, and few tanks are filled to the rim. Use the water level setting for the gap under the rim, and expect the water you actually add to be less than the calculated volume.
Weight of the water
A liter of fresh water weighs about one kilogram, which is about 8.35 pounds per US gallon. The figure is the water alone; the glass, the substrate and the stand add to it, so check what your furniture is rated to hold before you fill a large tank.