Asia dwarfs United States: about 44,580,000 km² km² against 9,439,424 km² km². At true size Asia is about 4.7× larger — the whole of United States fits into Asia roughly 4 times.
The old Mercator map treated both about equally (1× vs 2× inflation), so at least their relative sizes were preserved — even if both were drawn at the wrong absolute scale.
United States fits 4× into Asia.