Koji

A boy's name of Japanese origin with 611 recorded U.S. births.

Boy's name#4256 in 2024Rising fast

Meaning & Origin

A male given name from Japanese.

Koji is a boy's baby name of Japanese origin, with several possible meanings depending on the kanji used: kō (光, light; 幸, happiness) combined with ji (二, second son; 司, director; 治, govern), creating meanings like 'luminous second son' or 'governing light.'

Koji has the clean, two-syllable simplicity that makes Japanese names travel beautifully across cultures — easy to pronounce anywhere in the world while remaining distinctly Japanese. It gained international recognition through food science, as koji is also the fungus used in fermentation, associating the name with Japanese culinary tradition and craftsmanship.

EtymologyShow more

Koji first shows up in U.S. Social Security records in 1922. Its appearance in the 1920s coincides with waves of immigration, cultural exchange, and the early decades of American popular culture — all of which introduced and popularized new names.

Its Japanese classification suggests a path from japanese linguistic traditions into American usage, though the specific route — whether through immigration, literature, or cultural exchange — would require deeper historical research.

At a Glance

611

Total births

Since 1922

2023

Peak

33 births

1922

First recorded

103 years of data

Compare Koji with another name

Popularity Over Time

Koji climbed 1744 spots in the last 20 years — from #6000 to #4256.

First appeared: 1922Peak: 2023 (33 births)Current: #4256

Popularity by Decade

Decade-by-decade popularity data for Koji
Decade	Births	Avg Rank	Trend
2020s	115	#4758	▼
2010s	169	#5582	▲
2000s	146	#5684	▲
1990s	73	#6568	▲
1980s	65	#5769	▲
1970s	27	#4643	▲
1920s	16	#4411	—

The Story of Koji

A Gen Alpha name

Peaking in 2023, Koji is a fresh, modern favorite. Boys named Koji are most likely born between 2013 and 2024.

How rare is Koji?

Only about 1 in every 144,000 babies born in 2024 was named Koji — a truly uncommon choice.

The journey through the decades

First appeared in the records in 1922, gained momentum through the mid-century, peaked in the 2010s with 169 births that decade, and remains solidly popular today.

Koji by the numbers

Would fill 13 school buses
Meeting one Koji per day would take 1.7 years

Year-by-Year Data

View complete yearly data(48 years, 1922–2024)

Year-by-year popularity data for the name Koji
Year	Births	Rank	Change
2024	25	#4256	-8 (-24.2%)
2023	33	#3511	+7 (26.9%)
2022	26	#4144	+7 (36.8%)
2021	19	#5032	+7 (58.3%)
2020	12	#6846	-3 (-20.0%)
2019	15	#5978	+1 (7.1%)
2018	14	#6189	+1 (7.7%)
2017	13	#6518	-15 (-53.6%)
2016	28	#3843	+11 (64.7%)
2015	17	#5416	+2 (13.3%)
2014	15	#5883	-3 (-16.7%)
2013	18	#5083	+4 (28.6%)
2012	14	#6181	0
2011	14	#6118	-7 (-33.3%)
2010	21	#4613	+6 (40.0%)
2009	15	#5968	-6 (-28.6%)
2008	21	#4638	+4 (23.5%)
2007	17	#5331	+6 (54.5%)
2006	11	#7218	-7 (-38.9%)
2005	18	#4743	+5 (38.5%)

Source: U.S. Social Security Administration. Showing years with 5+ recorded births.

Frequently Asked Questions

Is Koji a boy's or girl's name?

Koji is primarily a boy's name.

When was Koji most popular?

Koji reached its peak popularity in 2023 with 33 births that year. It is currently ranked #4256 in the U.S.

How popular is the name Koji?

Koji is currently ranked #4256 in the U.S. (2024). It has been given to 611 babies since 1922.

Explore More

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Data source: U.S. Social Security Administration, 1922–2024