Sand Calculator?

[Anchovy]

I'm trying to buy everything I need for this tank before next week so we can get it set up. I have 120 lbs. of sand and was trying to figure out how much more I need. I was going to buy some live sand from CR, but I don't want to buy 40 lbs worth. I want it to be ~2 inches. I know there has to be some calculator I put in the dimensions of the tank and it spits out a number.....but I can't find it . Tank is 4 feet by 2 feet if someone just wants to give me the answer . Thanks!

 

[cee]

120 lbs. according to the RC calculator on the left-hand side of the "HOME" page for your dims and depth.

 

[Anchovy]

Thank you! I knew it was right in front of my face!