Seiji
Masculine
A Japanese name written in Roman letters has no meaning, because the meaning lives in the characters. Seiji can be written several different ways, each with a different sense: sincere and govern, pure and manage, refined and second son. The romanisation records only the sound.
How old is the name Seiji?
Seiji first appears in US birth records in 1914 — 111 years ago. The typical Seiji alive today was born around 2001, making them about 24 years old. About 400 people named Seiji are estimated to be alive in the US today.
When was the name Seiji most popular?
Seiji peaked in 1925, reaching #2435 nationally. Today it ranks #8910, 6,475 places below that high. See the whole 1925 chart.
Lists built from the same records:
Where it comes from
Origin, sound and short forms
The story of Seiji
Japanese writing gives most characters several readings, and personal names use that freedom more than any other part of the language, so a name is a pair of things: a sound and a set of characters, and neither determines the other. Two men called Seiji may have names written with no characters in common, meaning entirely different things, and two men whose names are written identically may pronounce them differently. Japanese forms often include a field for the reading in kana precisely because the characters do not settle it. When such a name is written in Roman letters, the half that carried the meaning is discarded and only the sound survives. That is why romanised Japanese names cannot be given etymologies in the way European ones can, and why any book that assigns a single meaning to Seiji has quietly picked one writing out of many.
Meaningnot established
Not established
Seiji has no single meaning, because Japanese names are written in kanji and the same reading can be spelled with many different character combinations. Common writings give elements such as sincere, pure, clear or refined for sei, and govern, manage or second son for ji. Without the characters, which American records do not preserve, the name's meaning is genuinely indeterminate. The peak is 1925.
Pronouncing Seiji
SAY-jee
Two syllables. Japanese has pitch accent rather than stress, so neither syllable is emphasized the way English would emphasize one. The ei is a long e sound.
Nicknames for Seiji
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
- 1914
- Most boys named
- 200719 — the highest on record
- Peak rank
- #2435reached in 1925
- Change vs 2024
- 0.0%8 in 2025, from 8
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.
Seiji in other languages
The same name elsewhere
- Seiji in Japanese — same name
- Seji in English — spelling variant
Seijis among us
people named Seiji are estimated to be alive in the US today
About 1 boy in 213,510 born in 2025 was named Seiji
Estimated from SSA birth records and published actuarial life tables. Method
Is it right for you
What happens to a name after it peaks
Fashion outlook
Seiji 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
Seiji beside its neighbors
The names ranked closest to Seiji in 2025, in babies rather than position — the bars are to scale.
US boys given each name in 2025.
The trade-off
- Five letters and two syllables, easy for English speakers.
- The -ji ending is a standard and recognizable Japanese male ending.
- The sounds are all straightforward in English.
- The meaning depends on characters the record does not preserve.
- English speakers will impose a stress pattern Japanese does not have.
- The 1925 peak places it in an early immigrant generation.
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Seiji
Masculine · #8910 in the U.S.
Frequently asked
- How many Seijis are there in the world?
- No country counts the world's names, so there is no worldwide figure — anyone quoting one is estimating. About 400 people named Seiji are estimated to be alive in the US today.
- How popular is the name Seiji in 2025?
- Seiji ranks #8910 among US boy names in 2025, with 8 babies given the name.
- How rare is the name Seiji?
- About 1 in every 213,510 US boys born in 2025 was named Seiji — 8 in all.
- Will my child share the name Seiji with classmates?
- Seiji will almost certainly be the only one in school.
Ranked beside Seiji
Names sitting at a similar level of popularity right now.
Davie#8910 · Ned#8910 · Darious#8910 · Alois#8910 · Len#8910 · Barton#8910 · Desmon#8910 · Winfield#8910
Looking for what else is popular rather than what resembles Seiji? See the current top 100.
Choosing between Seiji and another name?
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US figures from the Social Security Administration. 1880–2025. Data & methodology
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