Total births
90
Boys' name · since 2000
Kosei
Since 2000, U.S. Social Security records show 90 babies named Kosei, peaking in 2008. See the year-by-year trend, decade totals, and state rankings below, sourced from federal birth data.
- 90
- total births
- 2000–2020
- years on record
- 2010s
- peak decade
- 48%
- born in that decade
Kosei sits outside today's top ranks for boys, with 90 recorded since 2000.
According to the U.S. Social Security Administration, Kosei has been recorded 90 times among boys since 2000, though it is not among the currently most-used boys names, with its heaviest use in the 2010s. This profile covers year-by-year birth trends, decade totals, and state-level distribution, all derived directly from SSA birth-registration files spanning 2000 to 2020.
- 90 total births
- 2000–2020 years on record
- 2010s peak decade
- 48% born in that decade
Data updated Jun 2026
The verdict
90 boys have been named Kosei since 2000, peaking in the 2010s, last recorded in 2020.
- 90
- total births
- 2000–2020
- years on record
- 2010s
- peak decade
- 48%
- born in that decade
2010s
Peak decade
48% of everyone ever named Kosei was born in this single decade.
2008
Single peak year
9 babies were named Kosei in 2008 - its busiest year on record.
Kosei's usage pattern, beyond the headline number
Kosei splits its recorded history at 2011: 49% of all births land in the more recent half, 51% in the earlier half, an evenly balanced pattern over time. The single quietest year was 2000 (5 births) -- compare that against the 2008 peak of 9 for a sense of just how much the name's popularity has swung.
Kosei at a glance
Last recorded 2020Peak year
2008
Current rank
Unranked
Active since
2000
Kosei popularity over time
Annual U.S. births registered with the Social Security Administration · 2000–2020
- Peak year (2008)
- 9
- Annual births at peak, across 21 years of records
Kosei by decade
Total births in each ten-year window, peak vs trough at a glance
2010s was Kosei's strongest decade.
43 babies received the name during that ten-year window, about 48% of all-time use.
Kosei births by decade
Total births in each ten-year window
- 2000s
2000s
40 births
- 2010s
2010s
43 births
- 2020s 7
2020s
7 births
What this shows Peak: 2010s at 43 births (48% of all-time use).
Frequently Asked Questions
How popular is the name Kosei? ▼
90 babies have been named Kosei since 2000. It was last recorded in 2020. The peak year was 2008 with 9 births.
When was Kosei most popular? ▼
Kosei was most popular in the 2010s decade with 43 total births. The single peak year was 2008.
How long has the name Kosei been used? ▼
Records for Kosei go back to 2000, giving 21 years of history through 2020.
What names are similar to Kosei? ▼
Names with a similar sound or spelling include Kosta, Kostas, Koston, Kostantinos, and 4 more. These share a common prefix and are also used for boys.
What to do with Kosei's data
- Kosei's decade-level peak was the 2010s (43 total births); usage has since declined to 7 in the 2020s -- if you're weighing a "classic revival" angle, the trend line argues against it.
- Weighing it against an alternative? Put two names side by side. Compare names
Figures reflect SSA-reported births only; see the methodology above for the privacy-suppression floor.
Keep exploring Kosei
Nearby Names Like Kosei
Names with a similar sound, spelling, or feel to Kosei
Kosta Boy
#5492 417 births
Kostas Boy
372 births
Koston Boy
263 births
Kostantinos Boy
241 births
Kosisochukwu Boy
#13180 104 births
Compare Kosei side by side: Kosei vs Kosta Kosei vs Kostas Kosei vs Koston
Related Names
Names with a similar number of total births
Data Sources
Data as of June 2026. Source: U.S. Social Security Administration (SSA).
According to the Social Security Administration, this profile draws directly from the agency's public-use baby-name files (updated June 2026). See our methodology for the full extraction, aggregation, and privacy-suppression rules.
Primary: Source: U.S. Social Security Administration, Baby Names from Social Security Card Applications, National Data, 2000–2020 (ssa.gov/oact/babynames).
State-level: Source: U.S. Social Security Administration, Baby Names, State-Level Files (namesbystate.zip).
Cite this page
NameAlmanac Editorial. "Kosei: Baby Name Since 2000 - 90 Births, Peak 2008." NameAlmanac. Accessed via https://namealmanac.com/name/kosei. Licensed CC BY-SA 4.0.
Name Almanac is rendered directly from the Social Security Administration's public baby-name files, no number is typed in by an editor. This profile for Kosei draws directly on SSA national and state-level files, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of June 2026.