The difference in the up and down force is 0.069 pounds. Therefore each cubic foot of helium could lift 0.069 pounds. In order to lift 100 pounds (which would include the weight of your load, the balloon, and the helium) you would need 1449 cubic feet of helium.
Also, how much lift does helium generate?
It turns out that 1 liter of helium can lift a gram of matter so all you have to do is calculate your weight in grams; one pound equals about 453.6 grams (of course those of you reading this outside the U.S. and Liberia know your weight in grams so you can skip this part).
How many helium balloons would it take to lift a house?
(Most houses weigh between 80,000 and 160,000 pounds.) Given that 1 cubic foot of helium can lift 0.067 pounds, it would take 1,492,537 cubic feet of helium to lift the house—or about as much as would be contained in 105,854 balloons, each 3 feet in diameter.
How much hot air is needed to lift a person?
A little hot air
A typical hot air balloon holds 90,000 cubic feet of air and can lift 1,600 pounds. We can assume then that to lift a 200 pound person we would need about 12,000 cubic feet of hot air. But that air is very hot, as the typical hot air balloon is heated with a lot of propane.