What is the most common birthday?
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September 9 is the most common birthday in this collection: 259,228 recorded births, about 1 in 331 of all 85,712,738 U.S. births from 1994–2014.
9 of the ten most common dates fall in September. The rest fall in late July and August. It is a late-summer cluster.
September 9
Top 10 most common
Most common birthday
More common than 100%of other birthday dates.
1 in 331births in this sample share your birthday.
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- 259,228births on September 91994–2014, 21 occurrences
- 9 of 10top dates in Septemberthe rest in late July and August
- 11,811births per day in September#1 of 12 months
- 1 in 331births share this dateof 85,712,738 in the sample
The ten most common birthdays
All 366 dates from most to least common
All 366 dates sorted by recorded U.S. births 1994–2014, coloured by rarity tier, with the most common date marked.
| Date | Total births | Share of all births | |
|---|---|---|---|
| September 9 | 259,228 | 1 in 331 | |
| September 19 | 257,981 | 1 in 332 | |
| September 12 | 257,913 | 1 in 332 | |
| September 17 | 256,231 | 1 in 335 | |
| September 10 | 255,991 | 1 in 335 | |
| September 20 | 255,392 | 1 in 336 | |
| July 7 | 255,094 | 1 in 336 | |
| September 15 | 254,652 | 1 in 337 | |
| September 16 | 254,393 | 1 in 337 | |
| September 18 | 254,350 | 1 in 337 |
- September 9
- September 19
- September 12
- September 17
- September 10
- September 20
- July 7
- September 15
- September 16
- September 18
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Year by year
The busiest date changes from year to year. Each year has its own ranking, with the weekday every date fell on:
Elsewhere
Other countries rank differently. Each ranking below comes from its own national series:
Why September?
September has the highest births per day of any month in this sample: 11,811 births per day in September against 10,721 in January. See the full month ranking.
Counts are also much lower on fixed holidays, and on Labor Day and Thanksgiving, which fall on a different date each year. The holiday page measures those gaps. The counts show the association.
Related
The least common birthday · Browse all 366 dates · Does the same date rank first elsewhere?
Sources, method and limits
Main ranking: 85,712,738 recorded U.S. births on 7,670 calendar dates, 1994–2014. CDC/NCHS daily counts for 1994–1999 and Social Security Administration daily counts for 2000–2014, as compiled by FiveThirtyEight and attributed under CC BY 4.0. The overlapping years 2000–2003 are counted once.
Ranks compare totals across the 366 observed month-and-day dates. February 29 occurred 5 times in this window; every other date occurred 21 times, so per-occurrence figures are used wherever seasonality is compared.
Every figure above comes from the administrative records named here, at the granularity those records publish: a day, a month or a year. Coverage and definitions differ between countries and eras, so two sources are combined only where their documentation states the windows are separate, and the page where that happens says so.
Full method, leap-day treatment and definitions.
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