Sale at 220 East 57th Street #10C

look,
This is as close you would get including allowance for exterior walls (interior walls should be full counted). Here is how I calculated 560 sq ft:
Width of the apartment 11.75+7.25+1ft allowance for interior and exterior walls =20 ft
Length 20+8+1 foot allowance for walls = 29 ft.
Total = 29*20 = 580 + 10 (tiny section at the bottom) - 30 ( section on the bottom left = 560.

reposting
look,
This is as close you would get including allowance for exterior walls (interior walls should be full counted). Here is how I calculated 560 sq ft:
Width of the apartment 11.75 plus 7.25 plus 1ft allowance for interior and exterior walls =20 ft
Length 20 plus 8 plus 1 foot allowance for walls = 29 ft.
Total = 29*20 = 580 plus 10 (tiny section at the bottom) minus 30 ( section on the bottom left = 560.