Kai: meaning and UK use

What does Kai mean?

Kai means sea in Hawaiian. Separate Frisian/Germanic, Estonian and Chinese entries exist, so the Hawaiian meaning should not be applied automatically to every family using Kai.

Language or name family covered

Several independent origins

Meaning or derivation

Sea in the Hawaiian entry

Our browsing group

boy; modern, international

Browsing groups describe our editorial shortlist, not rules about who may use a name. A name can cross languages and genders.

Sources for this entry — reviewed 2026-10-07:

• Behind the Name — Kai

Pronunciation and related forms

/ˈkaj/ (Hawaiian IPA)

English respellings are approximate; IPA is labelled where used. Follow the pronunciation a person or family chooses, and check it with a speaker of the intended language if that connection matters to you.

No variants or nicknames have been verified for this entry. A family nickname does not need to be an established dictionary form.

How popular is Kai?

In 2025, 672 baby boys in England and Wales were registered as Kai, making it the 78th most popular boys’ name. That is down 6 places on 2024, when it ranked 72nd. It has held a similar position for a decade (86th in 2015). Its best year in the ONS series was 2011, at 56th. These figures cover England and Wales, not the whole UK.

2025 rank (boys)

78th

2025 registrations

672

Best rank in this series

56th (2011)

Every year from 1996 to 2025

Kai: rank and number of baby boys by year (ONS)

Year	Rank	Babies
2025	78	672
2024	72	735
2023	74	693
2022	72	799
2021	91	639
2020	103	579
2019	109	569
2018	100	634
2017	93	691
2016	87	794
2015	86	775
2014	77	858
2013	64	1,002
2012	63	1,075
2011	56	1,211
2010	56	1,308
2009	68	1,012
2008	68	1,057
2007	62	1,198
2006	63	1,213
2005	66	1,024
2004	62	1,044
2003	56	1,119
2002	59	1,037
2001	64	922
2000	73	723
1999	89	584
1998	100	528
1997	112	397
1996	161	212

The sum of published counts in this 1996–2025 boys series is 25,104. This is a lower bound where years are suppressed, not the number of living people with the name. A best rank is the best position within this series; it does not establish an all-time record.

Sources: ONS release, 2025; girls' dataset; boys' dataset. Our 20 top-ten positions were checked against Table 1 in the 2025 workbooks. The history chart and spelling comparisons come from the separate ONS 1996–2025 workbook, checked 7 October 2026. Spelling variants are separate entries. Scotland and Northern Ireland have separate statistics.

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Names to compare with Kai

These suggestions share a browsing group and one or more of our style tags or source-context labels. They are taste comparisons, not etymological relatives or a popularity ranking.

• Aaravinternational, modern · Crying, howling or noise
• Finnmodern, international · An Irish form of Fionn
• Lucainternational, modern · A form of Lucas or Luke
• Raffertymodern, international · Through Rabhartach, meaning flood tide
• Vihaaninternational, modern · Dawn or morning
• Zaynmodern, international · Beauty or grace

Read the UK naming guide for the difference between inspiration lists and official statistics, or return to the full name finder.

Registering or changing the name

Once you decide on Kai, confirm the registration process for your UK nation with the register office. If you later want to change a registered name, the route depends on the circumstances and may require consent from people with parental responsibility.

Start with GOV.UK birth registration or GOV.UK guidance on changing a child’s name. Our registration guide and child name-change guide explain where to find the relevant official process.