Cai vs Cailyn
American parents have registered 5,554 Cailyns since 1880, against 1,945 Cais. But in 2025 it was Cai that was commoner, 81 babies to 45.
Babies given each name, 1880–2025
Cai Cailyn
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
Of the 45 years in which either name was published, Cailyn for 35 years and Cai for 10 years. The lead changed hands once.
Side by side
| Cai | Cailyn | |
|---|---|---|
| Total US births | 1,945 | 5,554 |
| Most in one year | 131 | 401 |
| Babies in 2025 | 81 | 45 |
| Estimated living today | 1,900 | 5,500 |
| Median age today | 9 | 17 |
| Peak year | 2022 | 2009 |
| Best rank | 1,611th boys | 724th girls |
| Rank in 2025 | 2,108th | 3,712th |
| First recorded | 1989 | 1979 |
| Girls / boys | 495 / 1,450 | 5,549 / 5 |
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 Cailyns alive today are over 17; half the Cais are over 9. That is 8 years between them: two names in use at the same time, worn by two different generations.
Where each one is strongest
- Cai Florida (6.0×), Georgia (3.4×), Texas (3.3×)
- Cailyn Florida (2.3×), Georgia (1.9×), North Carolina (1.7×)
How much commoner the name is in that state than it is nationally, from births recorded since 1910.
Both names abroad
Countries whose statistics office publishes both names, so the comparison can be made somewhere other than the United States.
| Country | Cai | Cailyn |
|---|---|---|
| England and Wales | 2,757 | 87 |
| Scotland | 75 | 32 |
| Northern Ireland | 23 | 3 |
| Ireland | 18 | 5 |
Every spelling a country files separately is added together, over whatever years that country publishes — which is not the same range in any two of them, so read the columns against each other and not the rows.
Compare something else
Related comparisons
Social Security Administration birth records, 1880–2025, public domain. Full histories: Cai and Cailyn.