Juancarlos writes the Spanish double name Juan Carlos as one word, as it often appears on American birth certificates. Juan is the Spanish form of John, "God is gracious", and Carlos the Spanish Charles, "free man". King Juan Carlos I, who steered Spain's transition to democracy after 1975, is the most famous bearer. Juancarlos peaked at number 1,050 in 2004 in the United States and ranks number 2,696 among boys in 2025, with 48 births.