Koji
Masculine
Koji is a Japanese men's name, and like most Japanese names its meaning lives in the characters a family chooses rather than in the sound. The same two syllables can be written a dozen ways.
How old is the name Koji?
Koji first appears in US birth records in 1922 — 103 years ago. The typical Koji alive today was born around 2009, making them about 16 years old. About 600 people named Koji are estimated to be alive in the US today.
When was the name Koji most popular?
Koji peaked in 1984, reaching #2613 nationally. Today it ranks #3379, 766 places below that high. See the whole 1984 chart.
Where it comes from
Origin, sound and short forms
Our story of Koji
Ours, offered as ours. Koji was a very common Japanese men's name through the middle of the twentieth century, and what is interesting about it in Roman letters is what gets lost. In Japanese the name is a small choice with a meaning the family made deliberately — a character for filial duty, or for brightness, or for the second son. Written in English, all of that becomes two syllables and nothing else. That is a real loss, and it is worth naming rather than filling in with a guess.
Meaningnot established
Not established
The sound is fixed and the writing is not. Common character choices give elements such as wide, filial, light or second son for the first part and a very common name-ending character for the second, so a single Roman spelling stands for several distinct names.
Pronouncing Koji
KOH-jee
Two syllables, evenly weighted in Japanese, with a long first vowel that Roman spelling often drops.
Nicknames for Koji
Moderate
What the data says
146 years of official birth records
The long climb, and where it stands now
The same years in position rather than babies
- First recorded
- 1922
- Most boys named
- 202534 — the highest on record
- Peak rank
- #2613reached in 1984
- Change vs 2024
- +36.0%34 in 2025, from 25
Rank is a position, a count is a headcount, and they move independently — a name can hold its rank while the number of babies behind it falls. Source: U.S. Social Security Administration.
Koji in other languages
The same name elsewhere
- Koji in Japanese — transliteration
- Kouji in Japanese — spelling variant
Strongest US states over the last decade: California, Hawaii, Washington.
Kojis among us
people named Koji are estimated to be alive in the US today
About 1 boy in 50,238 born in 2025 was named Koji
Estimated from SSA birth records and published actuarial life tables. Method
Is it right for you
What happens to a name after it peaks
The Sipriano test
Every popular name lives one long story — a climb, a peak, a slow settling back. Koji's later chapters haven't been written yet, so we borrowed them: Sipriano climbed just as high around 1923, and its whole arc is on record. Line the two peaks up, and Sipriano's path sketches the road Koji is walking now.
Koji sits in the calm middle of the cycle — neither chasing a wave nor sliding off one. Middle-of-the-cycle names age slowly and predictably.
A scored estimate from 146 years of naming cycles — not a prophecy. Great names outlive statistics. How this is scored
Where Koji is headed
Koji looks set to keep climbing gently, with roughly 24% more babies a year by 2030 if the current curve holds. Its history is short or jumpy, though, so read this as a sketch rather than a promise.
Low confidence — fitted on official counts through 2025.
A damped-trend projection of the official birth data — a sketch of momentum, not a promise. Every name's forecast, ranked.
Koji beside its neighbors
The names ranked closest to Koji in 2025, in babies rather than position — the bars are to scale.
US boys given each name in 2025.
The trade-off
- Four letters and two syllables, readable at sight in English, Spanish and Japanese alike.
- A long and ordinary record as a men's name in Japan.
- Open, simple sounds that no language finds difficult.
- The meaning lives in characters a Roman spelling cannot carry, so the honest answer is a range.
- Koji and Kouji are the same name; the second marks a long vowel the first hides.
- In American English it is also a familiar word in food writing, for the fermentation mold.
Nobody names a baby alone.
Put Koji to the vote.
Add it to a family vote or a couple’s swipe deck — the other person gets one card, a simple answer and room to say why. No app, no account for them.
Only the people you invite can see your list.
Already decided on Koji? Hide it among decoys and let them guess.
What they receive
Someone added a name to your list
Koji
Masculine · #3379 in the U.S.
Frequently asked
- How many Kojis are there in the world?
- No country counts the world's names, so there is no worldwide figure — anyone quoting one is estimating. About 600 people named Koji are estimated to be alive in the US today.
- How popular is the name Koji in 2025?
- Koji ranks #3379 among US boy names in 2025, with 34 babies given the name.
- How rare is the name Koji?
- About 1 in every 50,238 US boys born in 2025 was named Koji — 34 in all.
- Will my child share the name Koji with classmates?
- Koji will almost certainly be the only one in school.
Ranked beside Koji
Names sitting at a similar level of popularity right now.
Art#3379 · Sampson#3379 · Kiernan#3379 · Benyamin#3379 · Quamir#3379 · Madhav#3379 · Tuff#3379 · Hubert#3379
Looking for what else is popular rather than what resembles Koji? See the current top 100.
Choosing between Koji and another name?
See them side by side — full stats, history and a gentle verdict.
Compare side by sideIn a hurry? Just pick a winner — one tap, no sign-up, and you see how everyone else voted.
Weighing a whole shortlist? Add the rest in the builder, or settle it with a bracket.
Cast your vote
Which one would you pick?
Your gut first, the numbers after — the split shows once you pick.
US figures from the Social Security Administration. 1880–2025. Data & methodology
No advertising trackers and no data sellinghow we handle your dataindependent and founder-run, about Name Battle