Kallan is a spelling of Callan, an Irish surname from Ó Cathaláin, a descendant of Cathalán, a diminutive of cathal meaning "battle" or "battle ruler". The K spelling matches the look of Kellan and Kallum, and the name fits the current taste for Irish surname names like Callum and Kieran. Kallan has climbed from number 3931 in 2016 to number 1912 in 2025, its best rank so far.