Kaj
Kaj is a boy's name that peaked in 2006, when it was the 4,520th most popular in the United States. In 2025 it ranked 12,008th. About 500 Kajs are alive in the United States today, and half of them are over 19.
Popularity, 1880–2025
boys named Kaj
By the numbers
- Total US births
- 515
- Estimated living today
- 500
- Median age today
- 19
- Peak year
- 2006
- Best rank
- 4,520th
- Rank in 2025
- 12,008th
- First recorded
- 1956
How old the living Kajs are
born that year still alive today
Of the 515 babies given the name since 1956, about 500 are alive — 97 in every hundred. The dotted line is the median: half were born before 2006 and half after.
An estimate, not a count. SSA births aged forward through SSA cohort life tables, which know nothing about who left the country or arrived in it — so for a name that mostly came to America rather than being born in it, this is a floor rather than a figure. Where you fall among living Americans.
Notable Kajs
- Kaj Leo Johannesen (born 1964)Prime Minister of the Faroe Islands from 2008 until 2015 and former soccer and handball player
- Kaj Munk (1898–1944)Danish playwright
- Kaj Franck (1911–1989)Finnish artist and designer
- Kaj Hendriks (born 1987)Dutch rower
- Kaj Sierhuis (born 1998)Dutch association football player
- Kaj Ramsteijn (born 1990)Dutch footballer
- Kaj Leo í Bartalsstovu (born 1991)Faroese footballer
People named Kaj with articles in the most Wikipedia languages. Data from Wikidata (CC0).
Where Kaj is most common
Relative to how many babies each state records, Kaj is most concentrated in California (9.9×).
Total births recorded in each state since 1910. Browse names by state.
Names of 2006
The most popular boys’ names the year Kaj peaked:
Kaj elsewhere
| Country | Spelling | Births | Best rank |
|---|---|---|---|
| Norway boys | Kaj | 308 | 211th |
| Poland boys | Kaj | 233 birth registrations | 234th |
| England and Wales boys | Kaj | 45 | 3,822nd |
| Belgium boys | Kaj | 26 | 1,068th |
| Ireland boys | Kaj | 3 | 770th |
Counts come from each country's own records and are not comparable with the US figures above, which cover different years and a different definition of a recorded name. Where a country writes the name several ways, the spellings are added together and the most common is shown. A row marked name registrations is counting something else: Portugal ranks each of a child's two given names separately, so a girl registered Maria Leonor is in both the Maria row and the Leonor row, and that figure is not a number of children.
Kaj: rank by region
In 2012, Kaj was given 5 times or more in 1 region of Belgium.
| Region | Spelling | Place | Children |
|---|---|---|---|
| Flanders | Kaj | 863 | 5 |
In 2024, Kaj was given 2 times or more in 2 regions of Poland.
| Region | Spelling | Place | Children |
|---|---|---|---|
| Dolnośląskie | Kaj | 255 | 2 |
| Mazowieckie | Kaj | 324 | 2 |
Each of these is the top of a list the statistics office cut off somewhere – Belgium below 5 children, Poland below 2 children – and published nothing after. So a region missing here is one where the name fell outside what was published, not one where it went unused. Places are shared where names tie, and the further down a list a place is, the more names can share it.
Kaj among the living
How many people each country's register counts under the name, rather than how many were given it in any one year. Each register was read on one date, and they are not the same date.
| Country | Spelling | First forename | Any forename |
|---|---|---|---|
| Finland boys | Kaj | 3,154 | 4,001 |
| the Netherlands boys | Kaj | 1,833 | 2,067 |
| the Netherlands girls | Kaj | 8 | 9 |
A count of people on a register – Finland on 4 August 2026, the Netherlands on 1 January 2018 – and not of births, so it cannot be compared with the figures above. Names with very few bearers are withheld, and a dash in the first-forename column means the register would not say rather than that nobody goes by it.
Related names
Kaj against another name
Two names on one chart, with the year one overtook the other.
Try it on yourself
Source: US Social Security Administration, national and state baby-name files, 1880–2025. Counts include only births registered with the SSA, and names with fewer than five births in a year are not published. The living estimate applies SSA cohort life tables to those births; it counts people born in the United States, so it misses anyone who arrived later and anyone who has left.