How common is your birthday?
Analysis of births* data from 1980 to 2013 shows:
- 28 September is the most common birthday
- the 10 most common birthdays all appear in the 13-day period from 22 September to 4 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 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 26 and 27 September).
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 1980–2013.
Published 9 April 2014