Ok. So the first link doesn't say the area. You didn't even calculate the area properly.
I calculated the area by simply multiplying the cabin length by the cabin width. Sure, not all area is usable for seating as I pointed, but isn't cabin area for other frames calculated the same way?
The second link is some random member of a forum.
Sure, it's from a member of a forum, it's not a fact, but it comes from the member Ferpe. In my opinion, he's one of the most knowledgeable members when it comes to the technical side of aviation, especially aerodynamics. You should check out his thread of wing design philosophy. That doesn't mean he can't be wrong though in calculating the cabin area.
Wikipedia page has no reference to 585m2. I typed A380 585 Wikipedia into Google and got no hits. The Wikipedia page does have 550m2. That's getting closer and that still doesn't include the stairs .
Wikipedia gives you the cabin length and width for each deck in the specification table at the bottom of the page, so I calculated it from there, and I got 595. You are right, there' s a 550m2 figure there, but it says it is the usable cabin area, not all of cabin area, which I calculated to be 595 very simply by multiplying length by width. You will say that's wrong, but at least this is how other frames are calculated too (at least this how I see it), so I guess we should use a common method for all frames.
The A380 is completely unique in that the upper deck has a foot closest to the sidewall that is completely unusable due to it curving inwards. It would be unfair to include this area. I could also include ceiling crew rests in the 777 as cabin area, as the A380 has to put crew rests in the cabin .
But it also has a bar area that isn't considered when calculating the usable cabin area, while in fact you can easily fill 4 rows in that area. Granted, it's not an apple to apple comparison due to its unique design.
The A380 wouldn't even be in the top 20 for empty weight per cabin area.
Not even top 20? Come on RJMAZ, that’s a bit too much
I know it's fat and some folks think it ain't pretty, but it still got a great CASM for a wide body. If you look at A380plus, it's got the one of the best CASM for any widebody, so its cabin area over weight can't be that bad.
I know you are good at such calculations. Please show how you get a proper cabin area for A380 and 787-10, let's see how it goes.