Seiji
A masculine Japanese name meaning "accomplished" or "composed".
Name Census estimates that about 398 living Americans carry the first name Seiji. The name is used almost exclusively for boys. The average person named Seiji today is around 24 years old, and the year with the single highest number of Seiji births was 2007 (19 babies).
This page is the full Name Census profile for Seiji. Below you will find a gender breakdown showing how the name splits between male and female registrations, a year-by-year popularity chart stretching back to 1880, decade-level totals, the top US states for this name, its meaning and etymology, and a set of frequently asked questions with data-backed answers.
For a British comparison, Name Census UK has a UK baby-name profile for Seiji with official rankings and popularity over time.
People living today
398
~ 1 in 861,192 Americans
Peak year
2007
19 babies that year
Average age
24
years old
2024 SSA rank
#9,694
Tracked since 1914
Census
Seiji in the 2020 Census
The 2020 Census recorded 635 people with the first name Seiji, which placed it at #17,398 in the published first-name tables. This is a snapshot of people who already had the name at the time of the Census.
The SSA sections elsewhere on this page answer a different question: how often parents gave the name to babies over time. The "people living today" figure on this page is different again: it is a current estimate built from SSA birth records and age-based survival rates, so the two numbers are not expected to match exactly.
2020 Census rank
#17,398
National first-name rank
People counted
635
635 in the published race/origin table
Per 100,000
0.2
People with this name in 2020
Largest reported group
Asian and Pacific Islander
58.9% of people with this name
Demographics
Ancestry and ethnicity for Seiji
In the 2020 Census race and Hispanic-origin table, the largest reported group for people named Seiji is Asian/Pacific Islander at 58.9%. The next largest groups are Two or More Races (26.1%) and Hispanic (8.3%). These figures describe the people who had the name in 2020, not any inherent property of the name itself.
The bar chart below shows how people with the first name Seiji described their own race and ethnicity on the 2020 Census form. The Census Bureau groups responses into six broad categories: White, Black or African American, Hispanic or Latino, Asian and Pacific Islander, American Indian and Alaska Native, and Two or More Races. When a category has too few respondents for a given name, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Percentages are shown so the breakdown is easy to read across every published category. Because the 2020 Census first-name file also includes raw headcounts for each group, Name Census can show those alongside the percentages in the legend and hover tooltip.
Keep in mind that these are self-reported numbers. A first name does not determine a person's race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the name Seiji at the time of the 2020 Census, not any inherent property of the name itself.
- Asian and Pacific Islander58.9% · 374
- Two or more races26.1% · 166
- Hispanic or Latino8.3% · 53
- Black or African American3.9% · 25
- White2.4% · 15
- American Indian and Alaska Native0.3% · 2
Popularity
Seiji: popularity over time
The SSA tracks Seiji from the 1910s through to the 2020s, spanning 9 decades of birth certificate data. The biggest single decade for the name was the 2000s, with 116 total registrations. Although the numbers have come down from the 2000s peak, Seiji remains solidly in use and shows no sign of disappearing from maternity wards.
Babies born per year
Decades
Seiji by decade
The table below breaks the full SSA timeline into ten-year windows. Each row shows how many male and female babies were given the name Seiji during that decade, along with a combined total. This is useful for spotting eras where the name surged or retreated.
Geography
Where Seijis live
Origin
Meaning and history of Seiji
The given name Seiji has its origins in Japan, where it has been used for centuries. The name is composed of two Japanese kanji characters: "sei" meaning "truth" or "sincerity," and "ji" meaning "child" or "son." Together, the name Seiji can be interpreted as "sincere child" or "truthful son."
In ancient Japan, the name Seiji was often given to boys as a symbolic wish for them to grow up with honesty and integrity. It was a popular choice among samurai families and the nobility, who placed great importance on values such as honor and truthfulness.
One of the earliest recorded bearers of the name Seiji was Seiji Tōgō (1836-1919), a prominent Japanese admiral who played a crucial role in the Russo-Japanese War of 1904-1905. His decisive victory at the Battle of Tsushima is considered one of the greatest naval battles in modern history.
Another notable figure in Japanese history with the name Seiji was Seiji Nagai (1886-1951), a Christian philosopher and author who survived the atomic bombing of Nagasaki in 1945. His book "The Bells of Nagasaki" recounts his experiences during the bombing and his efforts to help the survivors.
In the realm of literature, Seiji Tsutsumi (1927-1991) was a renowned Japanese novelist and playwright. His works often explored themes of social injustice and human resilience. He received numerous literary awards, including the Akutagawa Prize and the Naoki Prize.
The name Seiji has also been borne by influential figures in Japanese politics and business. Seiji Ozawa (born 1935) is a celebrated conductor and former music director of the Boston Symphony Orchestra. His contributions to classical music have earned him numerous accolades, including a Grammy Award.
Another notable bearer of the name was Seiji Natsume (1923-2005), a Japanese businessman who served as the chairman and CEO of Sony Corporation. Under his leadership, Sony became a global electronics powerhouse and a symbol of Japanese innovation and technological prowess.
While the name Seiji has its roots in Japan, it has also gained popularity in other parts of the world, particularly among individuals with Japanese ancestry or those with an appreciation for Japanese culture and values.
People
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.
Related
Other names starting with S
Other first names starting with S with a similar number of bearers.
FAQ
Seiji: questions and answers
How many people in the U.S. are named Seiji?
Name Census puts the figure at roughly 398 living Americans. We arrive at this by taking every SSA birth registration for Seiji going back to 1880 and adjusting each cohort for expected survival using CDC actuarial life tables. The result is an age-weighted living-bearer count, not a raw birth total. That works out to about 1 in 861,192 US residents.
Is Seiji a common name?
We classify Seiji as "Very Rare". It ranks above 82.3% of all first names in the SSA dataset by living bearers. Across the full history of the data, 509 babies have been registered with this name.
When was Seiji most popular?
The single biggest year for Seiji was 2007, when 19 babies received the name. The fact that the average living Seiji is about 24 years old gives you a rough sense of which era contributed the most bearers who are still alive today.
How common was Seiji in the 2020 Census?
The published 2020 Census first-name tables recorded 635 people with the name Seiji, or 0.21 per 100,000 residents. That placed it at #17,398 in the national Census ranking for first names.
Why is the Census count different from the living estimate?
Because they measure different things. The Census figure is a count of people who had the name Seiji in 2020. The living estimate aims to answer a current question instead: how many people with the name are alive today, based on SSA birth records and age-based survival rates. Since one number is a 2020 snapshot and the other is a present-day estimate, they are not expected to be identical.
What does the Census say about the gender split for Seiji?
In the 2020 Census sex table, Seiji leans strongly male. 612 people counted with this name were male (98.1%), compared with 12 female bearers (1.9%). The Census view is a snapshot of people living with the name in 2020, while the SSA section above tracks births across time.
What does the Census say about the background of people named Seiji?
In the 2020 Census race and Hispanic-origin table, the largest reported group for people named Seiji is Asian/Pacific Islander at 58.9%. The next largest groups are Two or More Races (26.1%) and Hispanic (8.3%). These figures describe the people who had the name in 2020, not any inherent property of the name itself. The percentages in the chart above come from self-reported race and Hispanic-origin responses in the 2020 Census.
Which group reports the name Seiji most often in the Census?
Asian/Pacific Islander is the largest reported group for people named Seiji in the 2020 Census, accounting for 58.9% (374 people in the published table).
Why can the Census sex total and race total differ slightly?
The Census Bureau published separate 2020 tables for sex and for race/Hispanic origin, and the released figures can differ slightly because of privacy protection in the public files. That is why this page treats the gender section and the race/origin section as two related snapshots instead of forcing them into one identical total.
Does every first name have Census demographic data?
No. The public Census first-name release only includes names that met the Bureau's publication rules, so many rarer names in the SSA files have no Census demographic snapshot. When that happens, the SSA trend, gender history, and state sections still appear, but the 2020 Census demographic sections are omitted.
What does the SSA popularity chart show?
The chart tracks births, not the number of people alive with the name today. Each point shows how many babies were given the name Seiji in that year. That makes it useful for spotting when the name rose, peaked, or faded.
Is Seiji a male name?
Yes, 100.0% of people registered as Seiji in the SSA data are male. You can see the full per-sex comparison in the gender distribution section above, which includes the latest year rank, birth count, and peak year for each sex.
Is Seiji still being used today?
Yes. The SSA still recorded Seiji in 2024, and the page above shows its latest-year rank where available. A name can be well past its peak and still remain in steady use, especially if it built up a large population over earlier decades.
Why can a name have a lot of living bearers even if it is not trendy now?
Because living-bearer counts and current baby-name popularity measure different things. A name like Seiji can build up a very large population over many decades, even if fewer parents are choosing it now than they did at its peak.
Where does this data come from?
First-name figures come from the Social Security Administration's national baby name files, which cover every name on a birth certificate from 1880 to 2024. Living-bearer estimates layer in CDC actuarial life tables broken out by sex to account for mortality. The population baseline (342,754,338) is the Census Bureau's latest national estimate. You can read the full calculation on our methodology page.
How many Americans are named Seiji?
HowManyOfMe.org, our sister site, answers that with the living-bearer count in one glance.