Aquarium Tank Weight Calculator

What this does

So you want to know what your aquarium will weigh, empty and full. This estimates both. Enter the tank's size, what it is made of, the water type, and the glass thickness, and it gives you the empty weight and the filled weight in pounds and kilograms. It is the number to check before you trust a stand or a floor to hold it.

How to use it

1. Enter the length, width, and height, with units.
2. Pick the wall type, glass or acrylic, and the water type, fresh or salt.
3. Enter the glass thickness in millimetres, then tap Calculate.

You will get an empty weight and a filled weight, each in pounds and kilograms.

How it works

It works out the water weight and the tank weight separately, then adds them. For the water, it finds the volume, converts to gallons, and multiplies by the weight of water:

water weight = gallons × 8.345

That 8.345 pounds is for fresh water, and salt water is a touch heavier at about 8.554 pounds per gallon, since dissolved salt makes it denser. For the empty weight, it estimates the glass or acrylic from the tank's surface area, its thickness, and a density figure, with glass coming out heavier than acrylic. The filled weight is simply the two added together. It all runs on your device.

Why the weight really matters

This is the part worth taking seriously. A filled aquarium is far heavier than most people expect, because water alone weighs about 8.3 pounds for every gallon, before you add the glass, the substrate, and the rocks. A 55 gallon tank comes in around 460 pounds filled, and a 75 gallon tank tops 600. That is a lot of weight sitting in one spot, so it needs a stand actually rated for it, and a floor that can take the load, ideally near a load bearing wall or across the joists rather than in the middle of a long span. Checking this before you fill the tank is a great deal easier than dealing with what happens if a stand or floor gives way.

Questions people ask