In Croatia, Kalc families are almost entirely Croats (from Bakar ), very rarely Slovenes (from Opatija ). In the past century, relatively most of Croatian residents bearing this family name were born in Rijeka and Sisak. In Hreljin in Bakar every eightieth inhabitant had the family name Kalc.
Prevalence
About 30 people with faimily name Kalc live in Croatia today, in 14 households. There were 20 of them in the middle of the past century, and their number increased by 30 percent. They are located in four Croatian counties, in 8 cities and two other places, mostly in Hreljin (<10), Novo Selo Palanjecko (<10), Zagreb (<5), Rijeka (<5), and in Opatija (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over five times, the first time 1906 in source Yearbook and Directory of Literary Society of St. Jerome 1906.