Tank Water Volume Calculator

by Scott Morell

Aren't there times when you want to know what the volume of water is in your tank? For example I have a 120 gallon tank that has about 140 lbs of rock and a 4 inch sand bed over a plenum. Now I know that it holds something less than 120 gallons of water.

GARF has been working on this calculator to provide a "Ball Park" estimate of the water volume of a tank. The sand bed and the live rock take up space in the tank. For example my 120 gallon tank with a 4 inch sand bed and 140 lbs. of live rock will have a ball park tank volume of 89 gallons of water.

  You can either select your tank from the list of standard size tanks, or enter the dimensions of your own custom built tank.

Select your tank from the list


Enter the dimensions in the form below:

Length: inches
Width: inches
Height: inches

Enter the information below

Depth of Sand bed:
Live Rock weight:

Calculated Values:

Tank Size:

Tank Water Volume:

*Note* This calculator bases the live rock volume at 7.48 gallons per 85 lbs of rock.