Romania is 4.2 times larger than Croatia.
Area: 56,594 km2 World Factbook
Population: 4,470,534 (July 2014) World Factbook
Croatia, officially the Republic of Croatia, is a unitary democratic parliamentary republic at the crossroads of Central Europe, Southeast Europe, and the Mediterranean. Its capital and largest city is Zagreb. The country is divided into 20 counties and the city of Zagreb. Wikipedia
Area: 238,391 km2 World Factbook
Population: 21,729,871 (July 2014) World Factbook
Romania, formerly also spelled Roumania and Rumania, is a country located at the crossroads of Southeastern and Central Europe, on the Lower Danube, north of the Balkan Peninsula and the western shore of the Black Sea. Wikipedia