How common is my birthday?
How common is a July 13 birthday?
How common is my birthday?
July 13
🙂 Pretty typical
#160 / 366
The 160th most common US birthday · about as common as the average date
More common than 56% of other dates · US births 1994–2014
namelette.com/birthdays/july-13
Fun facts about July 13
- The 13th effect: July 13 has 2% fewer births than the 6th and 20th of the same month, a dip often linked to people avoiding Friday the 13th for scheduled deliveries.
- July is the 3rd busiest birth month in the data.
- About 11,215 US babies were born on July 13 in a typical year (average over 21 years).
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Where these numbers come from
Real US birth counts for every day from 1994–2014 (21 years, 85,712,738 births), published by FiveThirtyEight: US_births_1994-2003_CDC_NCHS.csv (CDC National Center for Health Statistics) and US_births_2000-2014_SSA.csv (Social Security Administration). The files overlap in 2000–2003; we use CDC/NCHS for 1994–1999 and SSA for 2000–2014 so each year counts once.
Method: for each year we divide each day's births by that year's daily average (so bigger and smaller years count equally), then average that ratio for each calendar date across the years it exists. February 29 is averaged over the 5 leap years only (1996, 2000, 2004, 2008, 2012), so it isn't penalized for existing once every four years. Dates are ranked 1–366. Averaging over many years also evens out the weekday effect (fewer births on weekends). This is for fun, not a forecast.