How large is the city? That varies slightly depending on the version of the Bible. The ESV and NIV versions say it is 12,000 stadia in length and width(Rev. 21:16), where a stadia is 607 feet. This translates to 1,400 miles, which is what the NLT Bible says. However, the KJV and other versions say 12,000 furlongs, which translates to 1,500 miles.
Regardless of whether the city is 1,400 miles or 1,500 miles in length and width, it is shaped like a square at the base. This means New Jerusalem is larger than India with nearly 2 million square miles. These measurements are meant to be literal since they are described as man’s measurements(Rev. 21:17).
Even more astounding than the size at the base is the height that is also at least 1,400 miles(Rev. 21:16). This goes well beyond Earth’s atmosphere and into space. If a building in the city is this high and has a generous 12 feet per story, the building would be over 600,000 stories!
To give you a better idea just how big New Jerusalem is, here are some representations of what it would look like on Earth if the city is shaped like a cube.
Over North America:
Over the Middle East:
If you are 1 mile away from the city, you would not see the top2 but might if you are 10 miles away3. At 5,000 miles away, it would appear more than 130 times larger than the moon4. To appear the size of the moon, you would have to be 160,427 miles away.
Because the city is at least 1,400 miles in length, width and height, it could be shaped like a cube or pyramid. Does the height refer to the wall that surrounds the city or the tallest building? Rev. 21:17 says the wall around the city is about 200 feet, but ESV, NASB and KJV bibles don’t specify whether this is the thickness or height. The NIV bible says this is about 200 feet thick, but the footnote says “or high”. A cube-shaped city would make sense in the sense the Most Holy place in Solomon’s temple(1 Kings 6:20) was shaped like a cube. However, scripture does not provide a definitive answer as to whether the city is cube or pyramid-shaped.
1 http://www.cbs.gov.il/population/new_2009/table3.pdf
2 When describing how large something is when the distance to it grows, angular size is used. Angular size = 2arctan(1/2(d/D)) where d=height of New Jerusalem and D=distance to it. In this case the angular size is 179.84 degrees.
3 Angular size is 178.36 degrees
4 The moon is 30 minutes in angular size, at 1000 miles away, New Jerusalem is 4199 minutes