Kai vs Kaidin
American parents have registered 78,710 Kais since 1880, against 429 Kaidins. Kai is still ahead, with 4,002 babies in 2025.
Babies given each name, 1880–2025
Kai Kaidin
Each line is every baby given the name that year, girls and boys added together — the only count that means the same thing for both names. A line breaks where the name fell below five babies in a year — the point at which the SSA stops publishing it — rather than being drawn through a figure nobody published. A single published year in a gap shows as a dot.
Who was ahead
Kai has been the commoner name in every year either was published, 1926 to 2025. The lead has never changed hands.
The closest they came was 2005, when Kai had 1,598 and Kaidin had 31.
Side by side
| Kai | Kaidin | |
|---|---|---|
| Total US births | 78,710 | 429 |
| Most in one year | 5,732 | 34 |
| Babies in 2025 | 4,002 | under 5 |
| Estimated living today | 78,000 | 420 |
| Median age today | 8 | 16 |
| Peak year | 2022 | 2008 |
| Best rank | 59th boys | 3,286th boys |
| Rank in 2025 | 93rd | unranked |
| First recorded | 1926 | 2000 |
| Girls / boys | 8,478 / 70,232 | 11 / 418 |
A rank is a position within one sex’s list for one year, so the two rank rows are not subtracted from one another and the winning column is not marked on them. The living figure is a life-table estimate, not a count.
Which name is older
Half of the Kaidins alive today are over 16; half the Kais are over 8. That is 8 years between them: two names in use at the same time, worn by two different generations.
Compare something else
Related comparisons
Social Security Administration birth records, 1880–2025, public domain. Full histories: Kai and Kaidin.