Aquarium Calculator: How Many Gallons Can Your Tank Hold?

Want to know how much water your aquarium can hold?

Use our handy calculator to find out just how many gallons (or liters) of water your aquarium is capable of holding.

What do you want to find?
Tank Width
The distance across the front of your aquarium
Tank Height
The distance from the top to the bottom of your aquarium.
Tank Depth
The distance from the front to the back of your aquarium
Gallons
Liters
This is a small tank... So small in fact that it is unsuitable for most fish!
These tanks and bowls are often sold at bulk retailers by "experts" who will claim they are more than suitable for a single betta (they aren't)
Believe it or not, these small aquariums are actually the most difficult to keep and are unsuitable for beginners - good filtration is essential!
I recommend that any fish tank that is less than 10 gallons should only be considered by experienced aquarists who understand the risks and shortcomings of these tiny tanks, as well as how to overcome them.
This is a small tank... So small in fact that it is unsuitable for most fish!
These tanks and bowls are often sold at bulk retailers by "experts" who will claim they are more than suitable for a single betta (they aren't)
Believe it or not, these small aquariums are actually the most difficult to keep and are unsuitable for beginners - good filtration is essential!
I recommend that any fish tank that is less than 40 Liters should only be considered by experienced aquarists who understand the risks and shortcomings of these tiny tanks, as well as how to overcome them.
This is a mid-sized tank...
Perfect for beginners. Not so small that water quality is difficult to maintain but not so large that cleaning is a big hassle.
These tanks are large enough to house a wide range of fish, provided you are careful to research compatible fish that won't outgrow your tank.
30 - 75 gallons - This is a great starting size for a good marine or salt water tank.
This is a Mid-sized tank...
Perfect for beginners. Not so small that water quality is difficult to maintain but not so large that cleaning is a big hassle.
These tanks are large enough to house a wide range of fish, provided you are careful to research compatible fish that won't outgrow your tank.
110 -280 Liters - This is a great starting size for a good marine or salt water tank.
This is a large tank...
A tank this size can stock a wide variety of fish, plants, corals or decorations. You also can't deny that large tanks look stunning.
While that is undeniably appealing, you will need to work harder to clean and maintain this sized tank.
You should also note that, when filled with water, a tank of this size is incredibly heavy and you will need to make sure that your cabinet or floor can handle the load.
This is a large tank...
A tank this size can stock a wide variety of fish, plants, corals or decorations. You also can't deny that large tanks look stunning.
While that is undeniably appealing, you will need to work harder to clean and maintain this sized tank.
You should also note that, when filled with water, a tank of this size is incredibly heavy and you will need to make sure that your cabinet or floor can handle the load.

Notes on Aquarium Capacity:

Now that you know the volume of water that your aquarium can hold, you will want to be mindful of one fact:

Your aquarium will never actually hold this much water.

For instance, I have never met anyone who fills their aquarium all the way to the top of the tank. Any gap that you leave here will mean that there is less water in your tank.

Also, anything that you place in your tank will remove the same amount of water. Fish, rocks, coral, substrate, decorations… These all mean that there is less water in your tank.

Think of it as though you are filling your bath to the top with water and sliding in – the water is going to overflow because your body is taking up space where the water previously was.

Surface Agitation: Stir, Churn and Oxygenate Your Aquarium!

What the Heck Is the Aquarium Water Column?

What the Heck Is Bioload and Why Is It Important to Your Aquarium?

Ian Sterling

I've been keeping fish for over 30 years and currently have 4 different aquariums – it's an addiction. I'm here to teach you everything there is to know about fishkeeping.

I also use this site as an excuse to spend lots of money on testing and reviewing different aquarium products! You can find my reviews here.

Comments

Oscar lemence says
April 11, 2019 at 10:00 am
Hi!
Any suggestions on what kind of fish food that will not cloud the water…
I had 12”x21”x60” aquarium…
My fish is butterfly koi and goldfish…
- Ian Sterling says
  April 11, 2019 at 12:15 pm
  Hi Oscar,
  It’s unlikely that the fish food is the problem. It’s your stocking. You have too many fish for your aquarium. Read up on ALL the basics, like cycling your aquarium, how many fish can fit etc.
Rob Hopkins says
April 3, 2019 at 6:28 pm
I would like to use a tank that is set in angle iron frame, the tank measures 183cmX61cmX61cm, I can obtain 6mm glass. And do I need to put Kaolite (a sheet of expanded soft material) at the base, as it has a 2mm iron sheet at the base, welded in place.
Your advice would be most appreciated.
- Ian Sterling says
  April 4, 2019 at 4:26 am
  Hi Rob,
  Unfortunately, I don’t give construction advice via my blog. I highly recommend joining an online forum, where you can discuss the pros and cons of such a design.
Mike says
March 23, 2019 at 4:41 am
I purchased a tank used he told me it was 120 g when I looked at it seemed larger I measured it The measurment was 24 “×24″ ×60” so aprox
150 g and how much did it weigh had to bring it out to the truck then down to twisting steps
Either 270 lbs or 330 I have to figure out how to move it onto the bar top my self My brother inlaws will not move it again I suppose I will Mcguiver it 1
Danny Ryan says
February 26, 2019 at 11:24 pm
thanks very much for being here!
- Ian Sterling says
  February 27, 2019 at 6:39 am
  Thanks very much for this calculator!
Donald L Martin III says
January 14, 2019 at 2:38 am
Thank you.
bill says
October 21, 2018 at 5:24 am
I find it hard to believe that a 20x20x20 tank in cm is the same size as a 20x20x20 tank in inches. Please explain
- Ian Sterling says
  October 21, 2018 at 6:50 am
  Hi Bill,
  You are correct. It looks like something has gone wrong with the calculator. I’ll have my developer fix it up ASAP. For now the inches to gallons is working correctly.
Satya Rao says
September 8, 2018 at 9:54 am
Easy to calculate got 5 feet length and 2 feet depth and 2 feet width fish tank. Before loading with accessories wanted to know the gallons or litres of tank. Above calculator was a great help To identify
- Ian Sterling says
  September 8, 2018 at 11:12 am
  Hi Satya,
  Thanks for the feedback. I’m glad you found this helpful!
michael says
August 28, 2018 at 10:33 am
Does it include the sump pump? When I add chemicals do I add based on the display tank only or whole system?
- Ian Sterling says
  August 28, 2018 at 10:40 am
  Hi Miachael,
  For chemicals such as water conditioner, yes the sump is included. Let’s say you had a 100 gallon display tank and a 30 gallon sump. You would use 130 gallons when figuring out your dosage. Obviously this does not take into consideration any water displaced by decorations, rocks, driftwood, corals etc, so the reality is that the actual amount of water in your tank is less. As always, make sure you follow the instructions carefully when adding any chemical into your tank.
Jane says
August 26, 2018 at 8:53 pm
I have a 4 foot juwel tank how many gallons dose it hold please
- Ian Sterling says
  August 27, 2018 at 2:57 am
  Hi Jane,
  All you have to do is measure your aquarium and the calculator above will do the rest. A single dimension isn’t enough for me to give you an answer as to how much water your tank can hold.
Rhett says
July 29, 2018 at 1:12 am
Works good. 55 gallons is what my tank holds.
- FishLab Staff says
  July 29, 2018 at 7:01 am
  Hi Rhett,
  Glad we could help!
Nemo Percula says
July 26, 2018 at 5:16 am
Great calculator. Exactly what I was looking for. I was buying a new tank this weekend and now I know the water amount in the tank.
- FishLab Staff says
  July 26, 2018 at 5:22 am
  Hi Nemo,
  Glad we could help!

Aquarium Calculator: How Many Gallons Can Your Tank Hold?

Notes on Aquarium Capacity:

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