Sei
Boys' nameMeaning not yet documented
Sei has been given to 7 babies in the U.S. since 2007. It was used fewer than 5 times in 2025, so it doesn't appear in the latest year's list — today it's a genuinely uncommon pick. Its peak year was 2007, with 7 recorded.
Babies named Sei, 2007
1 in 571,000
Sei over time, 1880–2025
Based on births in the U.S. Babies given the name each year. Hover the chart — or focus it and use the arrow keys — for any year. Gaps mean the name was given fewer than 5 times that year; these counts are unpublished.
How common is Sei?
Sei had fewer than 5 recorded uses in 2025, so these figures use 2007, the last year it was published.
- Among all babies, 2007
- 1 in 571,000
- 7 of 3,997,748 births
- Among boys only
- 1 in 296,000
- <0.01% of boys
- Rank, 2007
- Unranked
- Fewer than 5 uses
- Coin-flip room size
- 395,862 kids
- Even odds of a second one
Where Sei sits on the popularity scale
Chance at least one other child shares the name
If the other children were drawn at random from the 2007 national name distribution. Real classrooms cluster by region and community, so treat these as a floor, not a ceiling.
Put another way: gather 395,862 children born in 2007 and it's an even bet that one of them is another Sei. In a class of 30 the chance is Under 1%.
When Seis were born
Half of everyone ever recorded as Sei was born before 2007 — so the typical Sei is around 18 today.
- Biggest decade
- 2000s
- 100.0% of all use
- Born in the last 25 years
- 100.0%
- A modern name
- Recorded since 1950
- 7
- People you could plausibly meet
2000s — 100.0% of all recorded uses (7).
Is Sei rising or falling?
Rank movement and count movement can disagree — the number of distinct names in use keeps growing, so a name holding a steady count still slides down the list. Both are shown.
- Rank vs 1 year ago
- —
- Not ranked then
- Rank vs 5 years ago
- New entry
- Not ranked then
- Rank vs 10 years ago
- —
- Not ranked then
- Births vs 10 years ago
- —
- Not published both years
- Share of its own peak
- 0%
- Peak was 2007 (7)
- Years since peak
- 18
- Years
- Year-to-year steadiness
- Not enough data
- Too few years
Sei around the world
Where Sei ranks in official birth records elsewhere in the world. Rankings only — the number of births isn’t comparable between places, so it isn’t shown.
- South Australia2008–2008#726in 2008
Popularity data from Consumer and Business Services (South Australia). CBS SA data under CC BY 4.0.
Sei by the numbers
The raw record for each sex the name is used for.
Names similar to Sei
Matched on shared beginnings and endings, similar length, and comparable popularity.
Sibling names for Sei
Names from the same era and popularity tier — the two things that make a sibling set feel deliberate — skipping lookalike spellings and shared initials.