United States is 38 times larger than United Kingdom.
Area: 243,610 km2 World Factbook
Population: 63,742,977 (July 2014) World Factbook
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom or simply Britain, is a sovereign state located off the north-western coast of continental Europe. Wikipedia
The United States of America, commonly referred to as the United States, America, and sometimes the States, is a federal republic consisting of 50 states and a federal district. The 48 contiguous states and Washington, D.C., are in central North America between Canada and Mexico. Wikipedia