UK boy's name
Kaj
A Scandinavian masculine name of uncertain origin, possibly derived from Old Norse word meaning "key".
For 2026, the newest official UK baby-name figures on this page are from 2021. That release is the current official benchmark rather than a forecast.
Kaj is a boy's name in the UK records. People looking for Kaj popularity in 2026 should use the latest official release, which is 2021 in this profile. In that release it ranked #4789, with 3 babies registered with the name. Its strongest year in the published records was 1996, with 4 births.
This profile covers 45 England and Wales registrations across 14 recorded years from 1996 to 2021. The figures come from ONS England and Wales, so the page is a view of published baby-name registrations rather than a forecast or a live count of people using the name today.
The latest count is about 75% of the recorded peak, which gives a quick read on how the name has moved since its high point.
We estimate that about 45 living people in the UK are called Kaj. This uses published birth registrations from England and Wales, Scotland and Northern Ireland, then applies ONS national life tables to estimate how many are likely still alive. It does not forecast extra births for 2022 or 2026.
Key insights
- • Kaj ranked #4789 for boys in England and Wales in 2021, with 3 registrations.
- • The name peaked in 1996, when 4 boys were registered as Kaj.
- • About 45 living people in the UK are estimated to have Kaj as a first name, after adjusting past birth registrations with ONS life tables.
Latest rank (E&W)
#4789
2021
Births in 2021
3
Latest year
Peak year
1996
4 births
Estimated living
45
2026
Meaning
What does Kaj mean?
The name Kaj originated from Scandinavia, particularly in Sweden and Denmark. It is a Nordic name derived from the Old Norse word "ká" or "kár", which means "to rejoice" or "to celebrate". The name first appeared in written records during the Viking Age, around the 8th to 11th centuries.
In ancient Norse mythology, Kaj was the name of a minor deity associated with fertility and joy. This connection to ancient pagan beliefs likely contributed to the name's early popularity among Nordic peoples.
One of the earliest documented instances of the name Kaj can be found in the Icelandic Sagas, a collection of historical narratives written in the 13th century. Specifically, the Saga of Erik the Red mentions a character named Kaj Óláfsson, who was a prominent landowner in Greenland during the 11th century.
Throughout the Middle Ages, the name Kaj remained relatively common in Scandinavia, particularly among the nobility and upper classes. A notable example is Kaj Lykke, a Danish nobleman and military leader who lived from 1598 to 1661. He played a significant role in the Danish-Swedish wars during the 17th century.
During the Renaissance period, the name Kaj gained popularity in other parts of Europe as well. One of the most famous individuals with this name was Kaj Munksgaard, a Danish printer and publisher born in 1858. He founded the renowned Munksgaard publishing house, which specialized in academic and scientific literature.
In more recent history, Kaj Franck, a Finnish designer and sculptor born in 1911, gained international recognition for his iconic glassware and ceramics designs. He is considered one of the leading figures in Finnish modernist design.
Another notable bearer of the name Kaj was Kaj Munk, a Danish playwright, pastor, and outspoken critic of the Nazi regime during World War II. He was born in 1898 and tragically executed by the Gestapo in 1944 for his resistance activities.
While the name Kaj has its roots in Scandinavia, it has also been adopted in other parts of the world, particularly among those with Nordic heritage or connections. For example, Kaj Stenvall, a Swedish-American ice hockey player born in 1951, had a successful career in the National Hockey League.
Sourced from namecensus.com.
Popularity
Kaj over time
The chart below shows babies named Kaj registered in England and Wales in the years where the name appears in the published records, from 1996 to 2021. Empty years are left out so rare names are not stretched across long periods where the published files do not show any registrations.
For Kaj, the clearest high point is 1996. The latest England and Wales figure is 3 births in 2021, compared with 4 at the peak.
Babies born per year
Decades
Kaj by decade
Decade totals smooth out the yearly jumps and make it easier to see whether Kaj was a short-lived spike or a name that stayed in regular use. Average rank is calculated only from years where a published rank exists.
| Decade | Average rank | Total births | Years covered |
|---|---|---|---|
| 2020s | #4699 | 6 | 2 |
| 2010s | #4385 | 10 | 3 |
| 2000s | #3646 | 19 | 6 |
| 1990s | #2734 | 10 | 3 |
Related
Names similar to Kaj
- Kieran 30,429
- Kyle 28,463
- Kai 24,432
- Kian 17,666
- Kayden 8,305
- Kevin 7,927
- Kane 7,149
- Kaiden 5,762
- Kieron 4,547
- Kacper 4,366
- Kye 4,012
- Kit 3,529
FAQ
Kaj: questions and answers
How popular is the name Kaj in the UK right now?
In 2021, Kaj was ranked #4789 for boys in England and Wales, with 3 births registered.
When was Kaj most popular?
The peak year on record was 1996, with 4 babies registered as Kaj in England and Wales.
What is the meaning and origin of Kaj?
A Scandinavian masculine name of uncertain origin, possibly derived from Old Norse word meaning "key".
How many people are called Kaj in the UK?
A total of 45 babies have been registered as Kaj across the 14 years of ONS England & Wales records shown here.
Which records is this page based on?
The England and Wales timeline uses ONS baby-name records. Scotland figures come from NRS and Northern Ireland figures come from NISRA. Counts are registrations in published baby-name files. The living estimate uses those birth registrations with ONS national life tables.