Hobby Know How Logo

How Much Does An Aquarium Weigh? (With Gravel and Water)

As an Amazon affiliate, we earn from qualifying purchases. I get commissions for purchases made through links in this post.

Aquariums can weigh in at much higher than they look. Therefore, before you buy one or decide where to put it, you have to know how much it weighs when empty and when it’s full.

The weight of most aquariums starts from 20 lbs, while some weigh 2000 lbs or more. The exact weight depends on the tank’s size, the material it's made out of, plus its contents. The attachments that come with the tank also contribute to its weight. 

aquarium hobby

For example, a 2.5-gallon tank filled only with water can weigh about 20.85 pounds; it gets heavier when you add stones or gravel.

Bearing in mind that the 2.5-gallon tanks are usually the smallest, it's easy to see how the big ones can weigh so much. 

This article will help clue you in on the possible weight of different sized tanks when filled with water or gravel. 

Why Does Tank Weight Matter?

As a newbie to the fish-keeping hobby world, you probably figure you'll just buy the tank and put it anywhere in your house. It’s that simple, right? Well, it's not that simple. 

Even if you have adequate space to hold your tank, it may be too heavy for your cabinet.

Heavy enough to crash through the floor. Also, you may have trouble moving it, imagine if you had to move houses? 

aquarium weight

The tank’s weight will also affect all the other accessories.

With these in mind, you need to know the tank’s total weight to determine where to put it and what to put in it.  

The Relationship Between Weight And Dimensions(With Water)

Since it's not possible to fill up a tank and weigh it before you buy, you'll want to be able to estimate the weight when it's full. 

You can use some basic rules to determine the weight based on the dimensions of the tank. 

As a general rule of thumb, a reasonable estimate for an empty tank’s weight is approximately 10 pounds for every gallon.

That means a 10-gallon tank weighs roughly 10 pounds. It can be higher or lower depending on what it’s made of.

Once you know how much it weighs empty, you will now use the tank’s dimensions to calculate how heavy it will be with water.

First, you need to calculate the tank’s volume using its length, width, and height.

You may want to take your tape measure with you to the store to make absolutely sure of the dimensions.

For example, a 12-inch long tank, 5 inches deep and 8 inches wide, would be about 3 gallons. 

Next, multiply the volume in gallons by 8.345 ( the weight of one gallon of water) for freshwater aquariums and 8.554 for saltwater tanks. 

In this example; 3*8.345= 25 lbs.

This means the 3-gallon tank would weigh 25lbs with freshwater and 26 lbs when filled with saltwater.

Here are some examples for different tank sizes filled with water:

Tank size (gallons)Dimension(inches)Empty weight (lbs)Filled weight Freshwater(lbs)Filled weight-saltwater (lbs)
10  20*10*12119294
20  30*12*1225208213
50 36*18*19100834855
18072*24*2543035883678

The Relationship Between Substrate And Weight (Gravel)

You will also want to know how much your tank will weigh when filled with gravel. To get it right, use the dimensions of the tank. 

This time, you need the length and width of the tank and an estimate of gravel depth in inches, then multiply by 0.05. Next, add this to the weight of the tank with water. 

The formula is: (L*W*DEPTH )*0.05

For example, for a 12-inch long tank, 8 inches deep filled with 2 inches of gravel, the gravel’s weight would be 9.6 pounds. 

            (12*8*2)*0.05= 9.6 pounds

This brings the total weight of the tank to 34.6 pounds ( 3 gallons, 25-pound tank with freshwater plus 9.6 pounds of gravel)

25 pounds + 9.6 pounds = 34.6 pounds

Here’s an example guide for tank weight with gravel (2-inch thick gravel layer)

Tank size (gallons)Dimension(inches)Gravel weight(pounds)Total weight(pounds)
10 20*10*1210104
20 30*12*1215228
50 36*18*1965920
18072*24*251723850

If you’re planning to add other materials like sand, you follow the same calculations, accounting for the substrate’s weight each time. 

The calculations may seem a bit complex, but thankfully you can find online calculators to do this. 

So, What’s The Weight Of An Aquarium?

Aquarium weight varies with the total weight of the empty tank plus the weight of its contents.

Using the example of a 10-gallon tank ( 20*10*12), it weighs 11lbs when empty, 92lbs when filled with fresh water, and 94lbs with saltwater. If you add gravel it increases to 104lbs.

The key takeaway here is, aquariums weigh quite a bit. Once you have identified the tank’s exact dimensions, do some math to figure out how much it will weigh when full.

It may be a good idea to use an online calculator to make it simple. Most importantly, make sure you’re placing your tank in a sturdy place to avoid any accidents. 

magnifier