Well, here are some numbers to make you think again! The circumference of the Earth is about 40,000 kilometers or 24,900 miles. This refers to how big the Earth is around it’s fattest middle part, like if you were to measure the length of a string going around the center of the Earth at the equator.he total surface area of the Earth is about 500,000,000 square kilometers. “Surface area” refers to all of the area of the lands surface, such as oceans and continents. It’s sort of like the total amount of space on the Earth that you could walk on or swim through.