Kay vs Kaydin
American parents have registered 102,545 Kays since 1880, against 1,852 Kaydins. Kay is still ahead, with 47 babies in 2025.
Babies given each name, 1880–2025
Kay Kaydin
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 142 years in which either name was published, Kay for 129 years and Kaydin for 13 years. The lead changed hands 2 times.
Side by side
| Kay | Kaydin | |
|---|---|---|
| Total US births | 102,545 | 1,852 |
| Most in one year | 3,718 | 152 |
| Babies in 2025 | 47 | 23 |
| Estimated living today | 62,000 | 1,800 |
| Median age today | 73 | 15 |
| Peak year | 1942 | 2010 |
| Best rank | 75th girls | 1,565th boys |
| Rank in 2025 | 3,903rd | 4,396th |
| First recorded | 1882 | 1999 |
| Girls / boys | 98,621 / 3,924 | 545 / 1,307 |
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 Kays alive today are over 73; half the Kaydins are over 15. That is 58 years between them: two names in use at the same time, worn by two different generations.
Where each one is strongest
- Kay South Dakota (3.1×), Iowa (2.7×), Wisconsin (2.6×)
- Kaydin Washington (4.5×), California (2.1×), Florida (2.1×)
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 | Kay | Kaydin |
|---|---|---|
| Scotland | 566 | 3 |
| England and Wales | 472 | 14 |
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: Kay and Kaydin.