Humanverse

Kay vs Kaylyn

American parents have registered 102,545 Kays since 1880, against 12,091 Kaylyns. But in 2025 it was Kaylyn that was commoner, 70 babies to 47.

Babies given each name, 1880–2025

Births per year: Kay against Kaylyn, 1880 to 2025 0 1k 2k 3k 4k 1880 1900 1920 1940 1960 1980 2000 2020

Kay Kaylyn

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 103 years and Kaylyn for 39 years. The lead changed hands once.

Side by side

  Kay Kaylyn
Total US births 102,54512,091
Most in one year 3,718464
Babies in 2025 4770
Estimated living today 62,00012,000
Median age today 7324
Peak year 19421997
Best rank 75th girls518th girls
Rank in 2025 3,903rd2,514th
First recorded 18821949
Girls / boys 98,621 / 3,92412,053 / 38

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 Kaylyns are over 24. That is 49 years between them: two names in use at the same time, worn by two different generations.

Where each one is strongest

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 Kaylyn
Scotland 56615
England and Wales 47261
Ireland 236

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 Kaylyn.