Tank size calculator
Gallons, liters and weight from a tank's dimensions, and which animals it can house as adults.
- Gallons
- 50
- Liters
- 191
- Water weight
- 421 lb
US gallons (231 cubic inches). A filled aquarium with glass and substrate weighs roughly 10 lb per gallon, about 505 lb here: check the stand and the floor.
Big enough for an adult (26)
- Betta Fish5 gal min
- Leopard Gecko36×18×18 in min
- Budgie30×18×18 in min
- Hermit Crab30×12×18 in min
- Axolotl29 gal min
- Goldfish40 gal min
- Tarantula12×12×12 in min
- Freshwater Shrimp5 gal min
- Praying Mantis8×8×12 in min
- Gerbil36×18×16 in min
- Pet Mouse30×12×12 in min
- Zebra Finch30×18×18 in min
- Pacman Frog24×18×18 in min
- Emperor Scorpion20×10×12 in min
- Canary30×18×18 in min
- Neon Tetra20 gal min
- Poison Dart Frog18×18×18 in min
- Guppy10 gal min
- Western Hognose Snake36×18×18 in min
- Mystery Snail5 gal min
- Angelfish29 gal min
- Isopods12×7×6 in min
- Musk Turtle40 gal min
- African Fat-Tailed Gecko36×18×18 in min
- Bristlenose Pleco20 gal min
- African Dwarf Frog10 gal min
Minimums from each animal's guide. Bigger is better for every one of them, and some need a specific shape: tall for climbers, long for snakes.
How the numbers work
How do you calculate the gallons in a tank?
Multiply length × width × height in inches and divide by 231, the number of cubic inches in a US gallon. A 36 × 18 × 18 inch tank holds 11,664 cubic inches, about 50 gallons. Real water volume is a little less once substrate and decor go in.
How many liters is that?
Multiply US gallons by 3.785. In centimeters, length × width × height divided by 1,000 gives liters directly.
How much does a filled aquarium weigh?
Water weighs about 8.3 lb per US gallon; with glass, substrate and rock a filled aquarium comes to roughly 10 lb per gallon. A 55-gallon tank is around 550 lb, which needs a purpose-built stand.
Why do reptile guides give dimensions instead of gallons?
Because gallons hide the shape. A 40-gallon breeder and a 40-gallon tall tank hold the same water but give very different floor space, and floor space and height are what a reptile uses.