I noticed that Cecil’s column on whether a coat could be made from the skin of a single person that he failed to mention the minimum requirements for a coat.
Knowing that a Japanese hanten is a very simple design for a coat with nice rectangular shapes, I looked up a pattern for it and ran the numbers. (Information from this page.)
In total there are five sections of cloth, assuming that I am reading things correctly. These measure:
2 X 42" X 17"
2 X 84" X 17"
1 X 8.5" X 101"
In square inches, this is 2X 714"[sup]2[/sup], 2 X 1428"[sup]2[/sup], and 731"[sup]2[/sup], for a total area of 5015"[sup]2[/sup]. In square feet that’s approximately 35’[sup]2[/sup]. So indeed, with only 14-18’[sup]2[/sup], a single average sized human will be insufficient.