What did the louisiana purchase do to the size of the united states

The Louisiana Purchase doubled the size of the United States.

Explanation:

The Louisiana Purchase occurred in 1803 between the United States and France, contrary to the provisions of the Treaty of San Ildefonso of 1800 between France and Spain.

Including interest, the United States finally paid $23,213,568 for this transaction. Funds for this purpose were lent to the Americans by British Barings Bank, despite the fact that Great Britain was at that time at war with France.  

The purchased land almost doubled the area of the United States at the time, making it one of the largest countries in the world. Eventually, 13 new US states arose from the purchased land and they constitute almost 25% of the current area of the United States.