Kaj is a rare boys' name that peaked in 2006 and has grown less common since.
Kaj is a boy name. In 2025 it ranked #12,947 for boy births in the United States (and #26,617 across all names), given to 5 babies. Kaj was first reported in SSA data in 1956 and peaked in 2006 (20 births).
| Year | U.S. births | U.S. + territories | Rank |
|---|---|---|---|
| 2025 | 5 | 5 | #12,947 |
| 2024 | 15 | 15 | #6,033 |
| 2023 | 8 | 8 | #9,346 |
| 2022 | 6 | 6 | #11,573 |
| 2021 | 10 | 10 | #7,862 |
| 2020 | 8 | 8 | #9,129 |
| 2019 | 8 | 8 | #9,304 |
| 2018 | 17 | 17 | #5,423 |
| 2017 | 10 | 10 | #7,864 |
| 2016 | 11 | 11 | #7,378 |
| 2015 | 15 | 15 | #5,870 |
| 2014 | 10 | 10 | #7,846 |
| 2013 | 12 | 12 | #6,815 |
| 2012 | 16 | 16 | #5,601 |
| 2011 | 19 | 19 | #4,905 |
| 2010 | 16 | 16 | #5,608 |
| 2009 | 20 | 20 | #4,839 |
| 2008 | 15 | 15 | #5,926 |
| 2007 | 11 | 11 | #7,345 |
| 2006 | 20 | 20 | #4,601 |
| 2005 | 10 | 10 | #7,399 |
| 2004 | 10 | 10 | #7,269 |
| 2003 | 14 | 14 | #5,410 |
| 2002 | 15 | 15 | #5,026 |
| 2001 | 10 | 10 | #6,708 |
| 2000 | 15 | 15 | #4,915 |
| 1999 | 12 | 12 | #5,494 |
| 1997 | 13 | — | #4,807 |
| 1996 | 13 | — | #4,750 |
| 1995 | 7 | — | #7,382 |
| 1994 | 6 | — | #8,279 |
| 1993 | 7 | — | #7,204 |
| 1992 | 8 | — | #6,394 |
| 1990 | 8 | — | #6,131 |
| 1989 | 7 | — | #6,579 |
| 1988 | 6 | — | #6,845 |
| 1986 | 12 | — | #3,763 |
| 1985 | 6 | — | #6,161 |
| 1984 | 12 | — | #3,572 |
| 1983 | 6 | — | #5,868 |
| 1981 | 5 | — | #6,780 |
| 1978 | 7 | — | #4,788 |
| 1977 | 7 | — | #4,858 |
| 1975 | 6 | — | #5,122 |
| 1974 | 6 | — | #4,936 |
| 1969 | 8 | — | #3,447 |
| 1968 | 5 | — | #4,428 |
| 1967 | 5 | — | #4,256 |
| 1966 | 6 | — | #3,722 |
| 1961 | 6 | — | #3,840 |
| 1956 | 5 | — | #4,205 |