Let's say each person gets a 72 inch tall, 30 inch wide, 20 inch deep box. That's about 28 cubic feet per person. If you stacked all 7B of these next to each other in a cube, you'd have a cube with a side of just 1.1 miles.
7 billion people in cramped boxes, some of them with limbs amputated and some of them with body parts in their box, with no ventilation, waste disposal or food supply. Sounds like a great xkcd what-if. That reminds me that you can fit 7 billion people on Rhode Island, but the geopolitical effects of that would be less than beneficial.
Let's say each person gets a 72 inch tall, 30 inch wide, 20 inch deep box. That's about 28 cubic feet per person. If you stacked all 7B of these next to each other in a cube, you'd have a cube with a side of just 1.1 miles.
http://instacalc.com/11188