Kailey has been given to about 27,254 people in the United States since 1880. It was most common in 2004, which makes it a millennial-parent name.
Its best year was 2004, when 1,449 babies were given the name, ranking 228th. The typical living American called Kailey is about 22 years old today. It is relatively most common in Illinois, where it accounts for 0.01% of births.
Source: US Social Security Administration, national and state name files, 2025 release, and the Office for National Statistics for England and Wales. Etymology researched and written by our editors. Living-population and median-age figures are our own estimates, described in the methodology.