Declining since 2010, #12,008 for boys today.
Popularity of Kaj since 1956
Babies named Kaj per year in U.S. Social Security records.
Data table (by decade)
| Decade | Boys |
|---|---|
| 1950s | 5 |
| 1960s | 30 |
| 1970s | 26 |
| 1980s | 54 |
| 1990s | 74 |
| 2000s | 140 |
| 2010s | 134 |
| 2020s | 52 |
Meaning & origin
Kaj is a Scandinavian name that has been in use in the United States since at least 1956. Though never extremely common, it saw its peak popularity in 2009, with a trajectory that indicates declining usage since 2010. As of 2025, the name ranks 12,008 and has a rarity factor of 1 in 341,615. It is typically a boy's name and is most common in Denmark and Sweden. The name does not appear in any U.S. state top-name lists, reflecting its niche appeal.
Kaj is a Scandinavian name, particularly common in Denmark and Sweden. It is often considered a short form of the Roman name Caius, though its exact etymology is debated. The name has been used in Denmark since at least the early 20th century, gaining modest popularity in the mid-1900s.
Nicknames & variants
Sibling names for Kaj
Names that share Kaj's style, for a brother or sister.
