How Many People Are Named Seiji?
An estimated 398 people in the United States have the first name Seiji. It is almost exclusively a male name. The average bearer is 24 years old, and Seiji peaked in popularity in 2007 with 19 births that year.
Below you will find a full statistical profile of Seiji as a first name in the United States, including gender data, a year-by-year popularity timeline going back to 1880, a decade breakdown, and state-by-state birth registrations. You can also check how many people share the full name Seiji paired with any surname.
Estimated Living Americans
398
About 1 in 861,192 people in the U.S.
Rarity
Very Rare
Predicted Gender
Male
100.0% confidence
Average Age
24
years old
Peak Year
2007
19 births
Total Registered
509
since 1880
Gender Distribution for Seiji
Seiji is almost exclusively a male name. Out of 509 total births registered, 100.0% were male.
Seiji as a male name
Ranked #9,694 in 2024
8 male births in 2024
Peak: 2007 (19 births)
Seiji: Popularity Over Time
SSA records for Seiji span from the 1910s to the 2020s, covering 9 decades of naming data. The most popular decade for this name was the 2000s, when 116 babies were registered. While Seiji is less common than at its peak in the 2000s, it remains a well-established name with steady registrations.
Seiji by Decade
How has Seiji tracked across different eras? The table below groups all SSA birth registrations into 10-year periods, with separate male and female counts. The colored bar shows each decade's share relative to the peak.
Seiji by State
Seiji + Last Name Combinations
How many people share a full name with Seiji as the first name? Click a combination below to see the estimate, or search any pairing.
Names Similar to Seiji
Other first names starting with S with a similar number of bearers.
Seiji: Questions and Answers
How many people in the U.S. are named Seiji?
We estimate approximately 398 people named Seiji are alive in the United States today. This is based on SSA birth records from 1880 to 2024, adjusted for mortality using CDC life tables. About 1 in 861,192 Americans share this first name.
Is Seiji a common name?
Seiji is classified as "Very Rare" and is more popular than 82.3% of all first names in the SSA database. A total of 509 births have been registered with this name since 1880.
When was Seiji most popular?
Seiji reached peak popularity in 2007, when 19 babies were given this name. The average age of a living person named Seiji is approximately 24 years old, reflecting when the name was most commonly given.
Is Seiji a male name?
Seiji is predominantly male. 100.0% of people with this name are male. See the gender breakdown above for full details.
How many Seiji Smiths are there?
To find how many people share a specific full name, we combine first name and surname frequencies. Try: Seiji Smith, Seiji Johnson, Seiji Williams. You can also search any combination on our homepage.
Where does this data come from?
Our estimates use Social Security Administration birth records (1880 to 2024), adjusted for survival using CDC 2023 life tables broken down by sex. The U.S. population figure (342,754,338) is from the Census Bureau's July 2025 estimate. Full methodology.
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