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Aquarium Water Volume Calculator

When buying a new fish tank, or, when considering whether or not you can add more fish safely to your current tank, it’s important to first know how much water volume your tank will hold. 


We often get asked questions from our customers on this topic - and that’s because it’s extremely important for a number of reasons, including:


  • Knowing how many fish you can safely keep in your tank 
  • Understanding how to treat the water with various dosages of chemicals 
  • Awareness of how often you should change or refresh the water to keep your fish healthy and happy.

To help you either decide on the size of aquarium you require, or to calculate whether you can home a brand new fish, we’ve developed a handy interactive tool, which allows you to calculate just how much water your aquarium can hold. 

SPLIT

Disclaimer: The above calculator is a tool which calculates the approximate capacity of water volume in your fish tank. It is designed to be used as a guide for this purpose only. Those using this tool for tank treatment do so at their own risk. Always follow the manufacturer’s instructions.

Calculate the volume of your fish tank

To easily calculate the volume of your fish tank, simply enter the length, width and height (in inches) of your fish tank, and our handy calculator will let you know how many litres of water your tank can hold. 


Our volume calculator also takes into account water displacement for things like stones, decorations and your fish. The ‘Empty Volume’ figure is the potential water capacity of your tank if completely empty. The ‘Realistic Volume’ figure represents the likely amount of water you will actually put in your tank, allowing for your fish, decorations and stones. This is a 10% adjustment - so if you have a tank that features lots of decorations, then simply consider this to be maximum water volume. 

 

Calculate how many tropical fish you can fit in your tropical fish tank*

Tank water volume can also be used to help decide just how many fish can fit into an aquarium. If you’re on the search for the perfect tank to keep tropical fish, but just have no idea what size you need to safely home your fish, then the below table can be used as a rough guide to help you find the perfect tank. 

Number of Small Tropical Fish (1 inch in length or less when fully grown)

Number of Medium Tropical Fish


(2 inches or less in length when fully grown)

TANK SIZE (Litres)

0

5

10

15

20

25

30

0

N/A

25 Litre

50 Litre

75 Litre

100 Litre

125 Litre

150 Litre

5

50 Litre

75 Litre

100 Litre

125 Litre

150 Litre

175 Litre

200 Litre

10

100 Litre

175 Litre

150 Litre

175 Litre

200 Litre

225 Litre

250 Litre

15

150 Litre

175 Litre

200 Litre

225 Litre

250 Litre

275 Litre

300 Litre

20

200 Litre

225 Litre

250 Litre

275 Litre

300 Litre

325 Litre

350 Litre

25

250 Litre

275 Litre

300 Litre

325 Litre

350 Litre

375 Litre

400 Litre

30

300 Litre

325 Litre

350 Litre

375 Litre

400 Litre

425 Litre

450 Litre

 

*Calculations for the above table are approximate and are based on one small tropical fish (1 inch in size) requiring 10 litres of water. Therefore, tropical fish two inches in size require 20 litres of water.

Looking for the right-sized fish tank?

 

If you’re looking for the perfect aquarium then look no further than our range here at Aquacadabra. We have one of the largest ranges of fish tanks on offer in the UK, complete with a whole range of tank accessories including pumps, filters, decorations, cleaning products, chemicals and more. 

 

We stock aquariums from 10 litres in size, ideal for a couple of small freshwater or tropical fish, right up to huge 500 litre plus aquariums - a perfect home for dozens of stunning fish, plants, snails, shrimp and more. 

 

Browse the full range today