Why is my tank smaller than the label says?

Labels use outside dimensions filled to the brim. Substrate, rocks, wood and the gap at the top usually take away 10 to 20 percent.

How heavy is a full aquarium?

Fresh water weighs about 8.34 pounds per gallon (1 kg per liter). Add roughly 10 percent for glass, gravel and decor, and make sure your stand is rated for it.

Fish tank volume calculator

Measure the inside of the glass, pick your tank shape, and get the volume in gallons and liters.

Measuring in

Tank shape

Length

Width

Height (water depth)

Use the water depth, not the glass height, for the most accurate number.

Result

Enter your numbers

Have a standard size? The tank size chart lists dimensions and liters for common tanks.

How to measure your tank

Measure the inside of the glass if you can. Outside measurements include the glass thickness, which adds a surprising amount on bigger tanks. For height, measure from the bottom glass to where the water actually sits.

How the math works

For a rectangle, multiply length by width by height. In inches, divide cubic inches by 231 to get US gallons. In centimeters, divide cubic centimeters by 1,000 to get liters. Cylinders use pi times the radius squared times height. Hexagons use 2.598 times the side length squared times height.

Why is my tank smaller than the label says?: Labels use outside dimensions filled to the brim. Substrate, rocks, wood and the gap at the top usually take away 10 to 20 percent.
How heavy is a full aquarium?: Fresh water weighs about 8.34 pounds per gallon (1 kg per liter). Add roughly 10 percent for glass, gravel and decor, and make sure your stand is rated for it.