Excavations have found the city to be 900 hectares in size. That translates to roughly 3.5 square miles or 9 square kilometers. The outer walls had a perimeter of 11 miles (18 kilometers). That's just the area of the city. The area controlled by/from the city would have been much larger but I'm not sure there's a way to accurately measure that.

Here's an image from a Brown University course page to give you an idea of the city's layout.

Source: A History of the Ancient Near East, CA. 3000 - 323 BC by Marc Van De Mieroop