When a data source on the site changes, it is logged here. How the numbers are built is on methodology.
11 October 2026
Each date page now shows Peru too, ranked on 3,053,148 births recorded from 2019 to 2025 in a daily table INEI prepared for RareBirthday. Its most common birthday is March 5 and its rarest December 25.
The world ranking now counts 27 countries, each once. September 20 is still the most common birthday and December 25 the rarest.
9 October 2026
Mexico is now ranked on 2017–2023, 12,934,170 births, with INEGI's birth registrations for 2025. Many Mexican births are registered a year or more after they happen, so a year joins once three years of registrations are in; 2024 waits for 2026's.
September 14 is still Mexico's most common birthday and December 25 its rarest. 89 dates moved by more than 25 places, and October is now its second most common month, August third.
9 October 2026
Each date page now shows Costa Rica too, ranked on 675,854 births recorded by INEC Costa Rica from 2014 to 2024. Its most common birthday is September 19 and its rarest January 1.
The world ranking now counts 26 countries, each once. September 20 is still the most common birthday and December 25 the rarest.
8 October 2026
Every date page is now ranked on live births by day of birth from the National Center for Health Statistics, for every day from 1989 to 2024: 142,623,862 births from one source. It replaces CDC/NCHS 1994–1999 plus SSA 2000–2014.
September 9 is still the most common birthday and December 25 the rarest. 47 dates moved by more than 50 places. The year chart now runs from 1969 to 2024 without a gap.
Months are ranked on their births per day with February 29 counted as the one day in four it is, so February is now #8 of the twelve in the United States and December #9.
8 October 2026
Each date page now shows that date in 24 other countries, each ranked on its own national records. The country menu that re-ranked the whole page is gone; every page is written around the United States.
Every country is now ranked the same way as the United States, ties going to the earlier date. That moves Denmark by one or two places on 70 dates.
Germany now runs to 2025 and France to 2024, the latest years we hold. Germany's most common birthday becomes August 8, was September 21, and France's September 20, was September 21.
18 September 2026
NCHS prepared a special tabulation of daily United States births for 2009–2024 for RareBirthday. Those years went on the year-by-year chart; the rank stayed on 1994–2014 until 8 October 2026.
17 September 2026
England & Wales, France, Germany, the Netherlands and Denmark use the order their statistics office published.
Updated October 2026