United Kingdom is 0.64 times as big as Japan
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK or U.K.) or Britain, is a sovereign country located off the northwestern coast of the European mainland. The United Kingdom includes the island of Great Britain, the northeastern part of the island of Ireland, and many smaller islands. Northern Ireland shares a land border with the Republic of Ireland. The total area of the United Kingdom is 94,000 square miles (240,000 km2).
Japan is an island country in East Asia located in the northwest Pacific Ocean. It is bordered by the Sea of Japan to the west and extends from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south. Part of the Pacific Ring of Fire, Japan comprises an archipelago of 6852 islands covering 377,975 square kilometers (145,937 sq mi); the country's five main islands, from north to south, are Hokkaido, Honshu, Shikoku, Kyushu, and Okinawa.