First off Id like to say hello and I am glad I found this forum. Reading threw some of the threads, it sounds like we have a great group of people here. I am trying to come up with a way to calculate the amount of chocolate being held in the chocolate reserve tank at my place of employment. Since we do not have a scale on this tank, my goal is to be able to take a measurement from the inside top of the tank to the top of the chocolate and be able to tell how many pounds we have left in the tank with that measurement. I will be sharing this with others in my workplace also, so I will be placing it in a spreadsheet so that it is easy for everyone to use. The tank has straight sides, but a rounded bottom. The straight sides were pretty easy for me to figure out, but once the chocolate is down farther than 63" (where the slope starts) I am having a hard time grasping a way to come up with a formula for that part of the tank. Being that im using an excel spreadsheet with VBA I dont need one big formula, everything can be split up into smaller formulas that will perform behind the scenes in the spreadsheet. The things that I do know are that a gallon of chocolate weighs 11.0995 lbs, and the bottom area that I am trying to figure out has a measurement from the top view of 192" x 90". From a side view of the tank(Small side 90") the tank appears to be a half circle with a 45" radius. That area of the tank holds 2,644 gallons or 29,347.078 pounds. The overall depth of the tank, at the center is 108". The bottom 45" is what I cannot figure out. Here are some images that may help.