Aquarium Volume Calculator

Use this calculator to estimate how many gallons or liters of water you need to fill an aquarium of a given size. Calculates the volume of the fish aquarium and the water required.

Calculation results

Aquarium volume 0.444 cubic yards (12 ft3)
Water needed 89.77 gallons
Water weight 747 lbs
Share calculator:

Embed this tool!
get code

Calculating aquarium volume and water needed

One often needs to calculate the volume of an aquarium in order to determine the amount of water needed to fill it, usually as a part of an estimation for the cost of maintaining the aquarium, including the water cost and the cost of appropriate aerators (a.k.a. oxygen pumps, air pumps, oxydators), chemicals, etc. Calculations for the weight of the water the aquarium will contain are required when deciding where you would like to place it. In either case the calculation process would be:

  1. Estimate the volume of water that will fill the aquarium by taking measurements or using the product specifications.
  2. Convert the volume to litres or gallons, depending on the unit you want the result to be in
  3. To get the water weight, multiply the volume by its density (in the same units). The density of water is ~62.2347 lb/ft3 (997 kg/m3) at room temperature.

When using this aquarium calculator, you should consider that the depth of the aquarium may not be the whole depth from top to bottom, but only the depth to which it can actually be filled. Some people incorrectly refer to the volume of an aquarium as "aquarium size". However, "size" would mean the external or internal dimensions of the aquarium, not its volume, although the two are related.

Volume and water calculations for non-rectangular aquariums

In some cases, the aquarium will have an irregular shape, for example the outer walls may be curved instead of straight. In such cases what you want to do is divide it in several rectangular-shaped sections, calculate their volume and water requirements using our calculator then sum them up together.

In case you end up needing to do this for a large number of sections, you might use our summation calculator. Reasonable approximations can be made for slightly irregular shapes by taking the average length or width, but in more complex scenarios and the need for an accurate water estimation you should consult a professional since it will likely require integral calculus.

fish aquarium volume

Knowing your aquarium's dimensions, volume and water contents are key in determining the appropriate pumps and other equipment, as well as chemical additives needed to maintain the environment as comfortable for the fish as possible and making sure you enjoy the company of your pets for longer.

Liters vs litres

Both "liter" and "litre" refer to the same unit, with "liter" being used in the United States while the conventional name as defined by the international body of standardization is "litre". Since both refer to the same volume or space, the two names can be used interchangeably.

Cite this calculator & page

If you'd like to cite this online calculator resource and information as provided on the page, you can use the following citation:
Georgiev G.Z., "Aquarium Volume Calculator", [online] Available at: URL [Accessed Date: 18 Feb, 2019].