How to say it
KAI
kaɪ
Masculine
Kai
Sea, or 'keeper of the keys'
What it means
Multi-origin. In Hawaiian, 'sea'; in Welsh, a form of Caius ('rejoice'); in Japanese, possible 'ocean' or 'shell'; in Frisian, a short form of Gerhard or Kaimund. The convergences are what make it cross-cultural.
Kai is a name with independent roots in several languages. The Hawaiian kai means 'sea.' The Welsh Cai (in Arthurian legend, Sir Kay, King Arthur's foster brother) traces to Latin Caius ('rejoice'). The Frisian Kai is short for names like Gerhard. In Japanese it can be written with characters meaning 'ocean,' 'shell,' or 'forgiveness.' The single syllable + the cross-cultural roots have made it one of the most-used unisex names in the US since the 2010s. It entered the top 100 in 2021. No shorter form needed.
How to spell Kai
The standard spelling is Kai. Common variants include Cai, Kye, but Kai is the most widely used form.
Popularity over time
peaked at #59 in 2022, currently #93 in 2025.
Source: U.S. Social Security Administration, names given to at least 5 babies in a year, 1880–2025. Reviewed July 2026. See where the names are moving
Heads-up notes
- Pop culture
Cobra Kai (the karate franchise) and Frozen II's Earth Giants have given Kai young-skewed cultural anchor; the older reference is the Snow Queen's boy character.
Who's worn it
Historical figures, characters, and public faces who share the name. The cultural surface, for whatever weight you want to give it.
- Kai (The Snow Queen) The boy whose heart freezes in Hans Christian Andersen's 1844 tale
- Kai Havertz German footballer, Arsenal and the German national team
Spelling variants
- Cai
- Kye
Names with the same feeling
See Kai from another angle
By meaning
By style
Common questions
- What does the name Kai mean?
- Multi-origin. In Hawaiian, 'sea'; in Welsh, a form of Caius ('rejoice'); in Japanese, possible 'ocean' or 'shell'; in Frisian, a short form of Gerhard or Kaimund. The convergences are what make it cross-cultural.
- What does Kai mean in Hawaiian?
- In Hawaiian, Kai means "Sea, or 'keeper of the keys'." Kai is a name with independent roots in several languages. The Hawaiian kai means 'sea.' The Welsh Cai (in Arthurian legend, Sir Kay, King Arthur's foster brother) traces to Latin Caius ('rejoice'). The Frisian Kai is short for names like Gerhard. In Japanese it can be written with characters meaning 'ocean,' 'shell,' or 'forgiveness.' The single syllable + the cross-cultural roots have made it one of the most-used unisex names in the US since the 2010s. It entered the top 100 in 2021. No shorter form needed.
- How do you pronounce Kai?
- Kai is pronounced kaɪ. Say it as KAI, with the stress on the "kai" syllable.
- How do you spell Kai?
- The standard spelling is Kai. Common spelling variants include Cai, Kye.
- Is Kai a boy or girl name?
- Kai is traditionally a masculine name.
- How popular is the name Kai?
- Kai ranked #93 in the U.S. in 2025, according to Social Security Administration data.