Chad is 18 times larger than Sierra Leone.
Area: 71,740 km2 World Factbook
Population: 5,743,725 (July 2014) World Factbook
Sierra Leone, officially the Republic of Sierra Leone, is a country in West Africa that is bordered by Guinea to the northeast, Liberia to the southeast, and the Atlantic Ocean to the southwest. Sierra Leone is a constitutional republic with a directly elected president and a unicameral legislature. Wikipedia
Area: 1,284,000 km2 World Factbook
Population: 11,412,107 (July 2014) World Factbook
Chad, officially the Republic of Chad, is a landlocked country in Central Africa. It is bordered by Libya to the north, Sudan to the east, the Central African Republic to the south, Cameroon and Nigeria to the southwest and Niger to the west. Wikipedia