Generally, you can get the volume of any regular object by multiplying it’s base area to it’s height. In school, we’ve all learnt that to calculate the area of a box, you must multiply its three sides: length, width and height. Since multiplying its length and width will give you the base area, it can be appreciated that the volume is still obtained by multiplying the base area to the height of the box. The same concept applies for aquaria.

Why do you have to find the volume?
Finding the volume of your aquarium is often important. Some reasons to know the volume of your aquarium are listed below:

  • To assess how many fish to add,
  • To calculate how much water to change,
  • To evaluate how much medication or fertiliser you should add, etc…

Fortunately, the calculation is very easy, both to calculate in litres or in gallons.

For simplicity, this tutorial is split into two parts:
1. Calculation of volume in litres
2. Calculation of volume in gallons

1. Calculation of the volume of your aquarium in litres

Step 1: Measure the length, width, and height of your aquarium in centimetres.
For example:
length: 60cm
width : 30cm
height: 30cm

Step 2: Multiply these three dimensions to get the volume in cubic centimetres(cc).
Volume = 60 x 30 x 30 = 54 000 cc

A little bit of theory: One litre is 1000 cubic centimetres. Note that one cubic centimetre (cc) is equivalent to one millilitre (ml).

Step 3: Divide the volume by 1000 to convert to litres
Volume in litres = 54 000/1000 = 54 litres.

That’s it! You now have the volume of your aquarium!

A shortcut you can use is to divide all the lengths by 10 and multiply the together to get the volume directly in litres.
That is, 6 x 3 x 3 = 54

2. Calculation of the volume of your aquarium in gallons
Step 1: Measure the length, width, and height of your aquarium in inches.
For example:
length: 24in
width : 12in
height: 12in

Step 2: Multiply these three dimensions to get the volume in cubic inches.
Volume = 24 x 12 x 12 = 3456 cubic inches

Step 3: Divide the volume in cubic inches by 231 to get the volume in gallons
volume in gallons = 3456/231 = 14.961 gallons (which is approximated to 15 gallons)