Kacper has been given to about 1,102 people in the United States since 1880. It was most common in 2007, which makes it a millennial-parent name.
Its best year was 2007, when 88 babies were given the name, ranking 1714th. The typical living American called Kacper is about 18 years old today.
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.