How common is your birthday?
Analysis of births* data from 1980 to 2015 shows:
- 30 September is the most common birthday
- the 10 most common birthdays all appear in the 10-day period from 22 September to 1 October
- the least common birthday is 25 December (apart from 29 February, which only occurs in leap years)
- the least common birthdays tend to be around public holidays: 24–27 December, 1–2 January, 6 February (Waitangi Day), 25 April (ANZAC Day).
A similar pattern occurs in Australia, England and Wales, and the United States.
Most common birthday table
Days are ranked 1 to 366 by number of births, where 1 is the most common birthday and 366 is the least common birthday. Some days are tied for ranking because they have had the same number of births (eg 7 and 15 October).
Shading is based on rank. Darker shading indicates more common birthdays, lighter shading indicates less common birthdays.
Click the image below to view a larger version of the table.
* Live births to mothers resident in New Zealand, registered in New Zealand during 1980–2015.
Updated 02 March 2016