Nearly a tie: Iran and Sudan differ by barely -13%% in area — about 1,622,847 km² km² against 1,863,027 km² km².
Iran sits in Asia, Sudan in Africa. On the old Mercator map the latitude gap distorted how large each felt beside the other; at true size the answer is simply 0.9×.
The old map muddied it further: Mercator inflates Iran about 1.4× and Sudan about 1.1×, so on a Mercator-style map this pair appears 1.1× apart instead of the true 0.9×.
Sudan fits 0× into Iran.