Aquarium volume calculator

Aquarium Volume Calculator
Tank Width The width of an aquarium is the distance across the front.
move slider or enter value
Tank Height The height of an aquarium is the distance from top to bottom.
move slider or enter value
Tank Depth The depth of an aquarium is the distance from front to back.
move slider or enter value
Your tank's volume is approximately 0.0 cubic inches or 0.0 U.S. gallons, which is approximately 0.0 liters. We recommend you SMALL aquariums.
Your tank's volume is approximately 0.0 cubic centimeters or 0.0 liters, which is approximately 0.0 U.S. gallons. We recommend you SMALL aquariums.

If you’ve been struggling to calculate your fish tank’s volume, you will be glad to know that we have our own sleekly designed aquarium volume calculator available on this page. Our calculator is super simple to use with an easily adjustable slider and offers two measurement units.

If you have never heard of aquarium volume calculators before, you might be wondering exactly what they are and why they exist right about now.

Related article: Best 3 Gallon Fish Tank

Simply put, they’re tools that let you calculate how much water your aquarium can carry, as knowing the maximum gallons of water a fish tank can hold is crucial for everyone with a fish tank, whether a newbie or expert.

Not knowing so can not only result in the wrong filtering and heating equipment (which is bad because an aquarium is an artificial ecosystem that needs to be maintained well for any fish or plant life to thrive) but also increases the risk of overstocking.

Aquarium calculators are also great for figuring out how big your tank needs to be if you want it to be able to hold a certain amount of water and help in selecting other appropriate equipment.

What do aquarium volume calculators do?

As mentioned earlier, an aquarium calculator turns your fish tank dimensions to gallons so you can know just how much water you can fit into your fish tank.

There are different calculators which can calculate volumes for different fish tank shapes like hexagons, bow-fronts, and quarter cylinders. However, some may require you to approximate measurements when dealing with more unique shapes.

And while you can choose to calculate your tank’s volume manually, these tools are very handy when trying to figure out the water holding capacity of bizarre and custom-shaped fish tanks and the filter sizes needed, something which can be tricky and needlessly frustrating to calculate manually.

Why do you need an aquarium volume calculator?

If you’ve been googling anything along the lines of ‘how to calculate water tank capacity gallons’, then you need an aquarium calculator.

Aquarium calculators convert your tank’s dimensions into how much space your aquarium has and how much water it can hold. This is useful when trying to determine if you have enough space for the kind of fish you’re thinking of getting.

The tool is also very useful when planning your aquarium and makes the process significantly easier. Some more reasons for using an aquarium calculator are:

  1. Accurate volumes. You obviously need an accurate idea of how much water your fish tank can hold. You could calculate it manually, but that would be quite the hassle. This is where these intuitive, easy-to-use volume calculators come in. All you need to do is feed them the data, and they will give you an accurate estimate of your tank’s volume.
  2. Space estimate. When you calculate your tank’s volume, you also get an accurate idea of the space you have. This knowledge is essential anytime you’re thinking of relocating or getting new fish, and an aquarium calculator can tell you exactly how much space you’ve got in a matter of seconds.
  3. Fish population. Different types of fish need different amounts of water, and it can be tricky to figure out the exact number and type of fish you can keep in your tank. Aquarium fish calculators help, but a lot of them need you to already know how much water your tank can hold in gallons or liters, and that can be quite challenging. Marine tank volume calculators help with that.
  4. Filter size. If you’ve already bought a tank and are now trying to figure out what filter size you’re going to need for it, a good rule of thumb is to choose a filter that’s big enough to filter the whole aquarium’s water about four times an hour. Just use an aquarium calculator to figure out the total water volume, and you’ll be good to go.
  5. Heater and chiller size. You might need a heater or chiller for your fish tank, depending on the time of the year or the type of fish you have. But how do you figure out what size to go with? Heater/chiller size also depends on your aquarium’s total water volume, which you can easily calculate using one of these fish tank volume calculators.
  6. Helps in planning. Setting up an aquarium takes a lot of careful planning, so you will need all the help you can get. Aquarium calculators help by giving you accurate facts to make sure everything goes smoothly and according to plan. Once you have the numbers, you can be confident in the rest of your calculations and sure that all your planning won’t be for naught.
  7. Convenient. While you can obviously try to calculate your fish tank’s volume manually, using a fish tank calculator is just so much easier and significantly more convenient. Especially when your tank is an uncommon shape or custom, and you don’t have access to an aquarium size chart.

How do aquarium calculators work?

Aquarium calculators apply the appropriate formulas to translate dimensions like length, height, width, and diameter, into volume which is a very useful three-dimensional quantity essential for any aquarium enthusiast.

How to use a fish tank calculator?

Fish tank size calculators are super easy and simple to use. All you need to do is:

  1. Measure. If you don’t have the aquarium’s packaging, use a tape measure to properly measure the dimensions of your tank. This includes height, width, diameter, etc.
  2. Input. Input the measured dimensions into the calculator and select the relevant unit of measurement.
  3. Done. And you’re done! Just wait a couple of seconds, and the calculator will let you know exactly how much space your fish tank has and how much water it can hold.


Fish tank volume is important information for any fish keeper, and there are times you need to calculate a tank’s volume because you’re redesigning your aquarium or getting new fish.

It is also essential when determining exactly how many fish you can keep in a tank and what heater/chiller wattage you have to go with for a fish tank of a certain size.

Not to mention, aquarium calculators are hassle-free, super easy-to-use, and give accurate results in just a matter of seconds compared to manual methods, which take much more time and have much greater chances of error.


About Me

My name is Jason Matthews and welcome to my website. When other kids were bragging about how their dog could sit and roll over, I was bragging about my latest Betta Fish and the cool sea castle I just added to his aquarium. 

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