Rei is a rare variant of Reign that peaked in 2019 and remains in steady use.
Rei is predominantly a girl name. In 2025 it ranked #5,364 among girls (24) and #3,363 among boys (35) — overall #5,058 across all names. The charts below show girls and boys separately.
| Year | U.S. births | U.S. + territories | ♀ Rank | ♂ Rank |
|---|---|---|---|---|
| 2025 | 59 | 59 | #5,364 | #3,363 |
| 2024 | 56 | 56 | #4,997 | #3,874 |
| 2023 | 46 | 46 | #4,968 | #5,203 |
| 2022 | 40 | 40 | #5,940 | #5,175 |
| 2021 | 67 | 67 | #4,304 | #3,404 |
| 2020 | 64 | 64 | #3,269 | #5,643 |
| 2019 | 67 | 67 | #3,985 | #3,698 |
| 2018 | 61 | 61 | #4,328 | #3,865 |
| 2017 | 62 | 62 | #3,829 | #4,565 |
| 2016 | 41 | 41 | #5,098 | #6,277 |
| 2015 | 34 | 34 | #8,844 | #4,673 |
| 2014 | 14 | 14 | #18,627 | #8,639 |
| 2013 | 17 | 17 | #10,107 | #11,841 |
| 2012 | 24 | 24 | #7,718 | #9,514 |
| 2011 | 35 | 35 | #6,297 | #6,182 |
| 2010 | 29 | 29 | #8,618 | #5,972 |
| 2009 | 22 | 22 | #12,232 | #6,728 |
| 2008 | 31 | 31 | #11,425 | #4,670 |
| 2007 | 29 | 29 | #8,436 | #6,195 |
| 2006 | 16 | 16 | #13,345 | #9,372 |
| 2005 | 21 | 21 | #8,756 | #8,925 |
| 2004 | 26 | 26 | #8,612 | #6,066 |
| 2003 | 30 | 30 | #7,909 | #4,990 |
| 2002 | 24 | 24 | #8,710 | #5,996 |
| 2001 | 15 | 15 | #13,168 | #8,149 |
| 2000 | 10 | 10 | — | #6,719 |
| 1999 | 18 | 18 | #10,142 | #6,971 |
| 1998 | 10 | 10 | — | #6,196 |
| 1997 | 7 | — | — | #7,939 |
| 1995 | 6 | — | #12,994 | — |
| 1992 | 5 | — | — | #9,508 |
| 1991 | 5 | — | #14,831 | — |
| 1990 | 7 | — | #11,080 | — |
| 1989 | 7 | — | #10,558 | — |
| 1988 | 7 | — | #10,092 | — |
| 1987 | 11 | — | #10,916 | #7,873 |
| 1974 | 5 | — | #9,820 | — |