Kai
Kai was the 93rd most popular name for boys in 2025, given to 3,768 babies. Its best year was 2022, when it ranked 59th with 5,374 babies. Over the last ten years it has moved up 52 places. More babies were named Kai in the 2010s than in any other decade.
Meaning Origin uncertain · Scandinavian, Frisian, Hawaiian, Welsh
Say it KY /kaɪ/
- Rank in 2025
- #93 boys, unchanged since 2020
- Babies in 2025
- 3,768boys
- Girls and boys
- 6% girls, 94% boys2021–2025
- Peak year
- 20225,374 babies
- Total since 1880
- 78,710babies recorded
What does the name Kai mean?
Kai has several separate sources that happen to share a spelling. In Scandinavia and Germany, Kai or Kaj has been used for centuries; it may come from a Latin name like Caius or, in Frisian, from pet forms of longer names. Welsh Cai, Sir Kay of Arthurian legend, is another Latin-derived form. In Hawaiian, kai is the common word for 'sea', and many American parents choose the name with that meaning in mind. Japanese and other languages have their own unrelated names and words spelled Kai.
kai (Hawaiian, “sea”)Caius (Latin, “Roman name (possible source of Scandinavian Kaj)”)
How sure is this? Uncertain. Several unrelated origins; the Scandinavian and German name's ultimate source is not settled. The Hawaiian word meaning is clear, but whether a given family uses it in that sense varies.
See also: Scandinavian names.
Sources for this meaning
- Wiktionary, entry 'Kai', Wiktionary (Wikimedia Foundation); facts restated, no text reused
- Wiktionary, entry 'kai', Wiktionary (Wikimedia Foundation); facts restated, no text reused
- Wikipedia, 'Kai (name)', Wikipedia (Wikimedia Foundation); facts restated, no text reused
Kai popularity since 1880
| Year | Rank (girls) | Rank (boys) | Babies (girls) | Babies (boys) |
|---|---|---|---|---|
| 2025 | #1,054 | #93 | 234 | 3,768 |
| 2020 | #793 | #93 | 344 | 3,867 |
| 2010 | #955 | #205 | 268 | 1,750 |
| 2000 | #1,416 | #403 | 131 | 622 |
| 1990 | #2,415 | #928 | 51 | 124 |
| 1980 | #1,739 | #994 | 64 | 83 |
| 1970 | #3,153 | #1,074 | 21 | 58 |
| 1960 | #5,411 | #1,842 | 7 | 20 |
| 1950 | — | #2,671 | — | 9 |
| 1940 | — | — | — | — |
| 1930 | — | — | — | — |
| 1920 | — | — | — | — |
| 1910 | — | — | — | — |
| 1900 | — | — | — | — |
| 1890 | — | — | — | — |
| 1880 | — | — | — | — |
How popular is Kai, counting every spelling?
Kai is the most common spelling of a name family that ranked #96 for boys in 2025 once every spelling is counted together, compared with #93 for Kai on its own. Together these spellings went to 3,837 boys in 2025.
| Spelling | Babies 2025 | Official rank | Babies 2021–2025 |
|---|---|---|---|
| Kai | 3,768 | #93 | 23,060 |
| Cai | 69 | #2,113 | 433 |
Spellings count together when they sound the same in American English and are used for the same sex; nicknames and forms that sound different (such as Theo and Theodore) are kept apart. How we group spellings.
How many kids will share the name Kai?
3,768 of the 3,606,400 babies born in the US in 2025 were named Kai (1.04 per 1,000 births). For a boy named Kai born in 2025, the chance that another child with the same name is in a class of 20 children the same age is under 1 in 50. If every grade liked the name as much as the 2025 babies do, only about one elementary school in 2 (of 430 pupils) would have a child named Kai.
Shares of all registered births (NCHS); classes assumed to be children born the same year. How we estimate this.
How old are people named Kai?
About 69,300 people born in the US named Kai are alive today, with a median age of 9; half are between 4 and 16. That makes Kai a young name: most people with it are children.
Babies given the name each year (SSA) times the share of that birth year still alive (SSA life tables). Counts people born in the US only. Method.
Kai by state
How common Kai was among boys born in each state in 2021–2025. It is notably more common than nationally in Hawaii (4.9×), Alaska (2.5×), District of Columbia (2.2×), Rhode Island (1.7×), New Mexico (1.7×). It is least common, relative to the national rate, in Vermont, New Hampshire, Kentucky.
Names with a similar history
These names rose and fell in step with Kai: their share of US boys followed the most similar curve since 1880. If you like Kai, they share its era and feel.
Middle names for Kai · Sibling names for Kai
Kai is also a nickname for Malachi, Malakai and Makai.
Questions about the name Kai
What does Kai mean?
The origin of Kai is uncertain: several unrelated origins; the Scandinavian and German name's ultimate source is not settled. The Hawaiian word meaning is clear, but whether a given family uses it in that sense varies.
How popular is the name Kai?
Kai was the 93rd most popular name for boys in 2025, given to 3,768 babies. Its best year was 2022, when it ranked 59th with 5,374 babies. Over the last ten years it has moved up 52 places. More babies were named Kai in the 2010s than in any other decade.
Is Kai a boy or girl name?
In 2021–2025, 6% girls, 94% boys given the name Kai in the US.
Where is Kai most popular?
In 2021–2025, Kai was most common in Hawaii (13.20 per 1,000 boys), followed by Alaska and District of Columbia.