How common is your birthday? Check out the full list, plus uncommon celebrity birthdays.
Do you know someone who has the same birthday as you?
According to the "birthday paradox," in a random group of 23 people, there is about a 50% chance two people will share a birthday. Any more than that, and it gets increasingly likely that a pair of matching birthdays exist.
According to birth data from the Centers for Disease Control and Prevention and the Social Security Administration, here are the most popular days to blow out the candles in the United States.
What is the most common birthday?
The most common birthday is Sept. 9. In second and third place are Sept. 19 and 12.
In fact, the entire top 10 list is made of September birthdays between Sept. 9 and 20. Count backward and you’re just in time for the holidays, since pregnancy is an average of 40 weeks from last menstruation.
Why the holidays? Perhaps because there’s more holiday cheer in the air, and it could have something to do with the fact that many people have free time on vacation days they take around Christmas and New Year’s, to celebrate with family and friends. There’s also the general sense of romance around the holidays — December is the most popular month to get engaged. One study even found a 9.1% peak in conception at the end of the year.
Scroll down to check out the full list of birthdays from most to least common.
Celebrities born on Sept. 9
If you were born on the most popular day of the year, here are a few celebs you share a birthday with:
Adam Sandler
Hugh Grant
Michelle Williams
Michael Bublé
Eric Stonestreet
Zoe Kazan
William Miller
Kelsey Asbille
Henry Thomas
Constance Marie
It's Sagittarius season: Check out these 30 celebrity fire signs
What is the most common birth month?
Though September dominates the top ten most common birthdays, August is actually the most common birth month.
According to the birth data, there were just under 7,600,000 births in August between 1994 and 2014. The second most common birth month is July, with 7,500,795 births and September in third place with 7,411,299. It’s worth noting, though, that both July and August have 31 days in the month while September only has 30. The least common birth month is predictably February, which only has 28 days.
Birth months of the year, in order of most common to least common:
August
July
September
October
May
December
March
June
January
November
April
February
What is the rarest birthday?
The least common birthday is leap day, or February 29. But because the day only occurs once every four years, it’s obvious it would yield the least amount of birthdays.
The rarest birthday of the 365 annual calendar days is Christmas Day, Dec. 25.
If your birthday is New Year’s Day or Christmas Eve, you also have uncommon birthdays. Jan. 1 and Dec. 24 are just below Christmas on the list.
Late November birthdays are also pretty rare as Thanksgiving celebrations ramp up in the United States. Nov. 23-28 all fall between 354 and 360 out of the 365 calendar days. And July 4th, which occurs in the second most popular birth month, is 363rd on the list.
According to a working paper from the National Bureau of Economic Research, there are 18% less births on the day of and just after a holiday. Around half of the decline is due to fewer cesarean sections scheduled on holidays, in part because of low hospital staffing numbers on the holiday and cultural attitudes — parents’ desires to separate fixed holidays and birthdays.
Celebrities born on Dec. 25
If you're a Christmas baby born in Capricorn season, here are the famous figures you share a birthday with:
Jeremy Strong
Justin Trudeau
Jimmy Buffett
Clara Barton (1821-1912)
Humphrey Bogart (1899-1957)
Annie Lennox
Rod Serling (1924-1975)
Birthdays: Most common to least
Sept. 9
Sept. 19
Sept. 12
Sept. 17
Sept. 10
July 7
Sept. 20
Sept. 15
Sept. 16
Sept. 18
Dec. 20
Sept. 26
Sept. 8
Sept. 23
Dec. 29
Aug. 8
Sept. 24
July 8
Dec. 19
Aug. 29
Aug. 15
Sept. 22
Dec. 30
Sept. 14
Sept. 25
Sept. 27
July 1
Dec. 28
Aug. 28
July 2
Aug. 22
Sept. 21
Sept. 13
Aug. 30
July 11
Aug. 16
Aug. 1
July 18
Aug. 20
July 9
July 16
July 25
July 15
Aug. 12
July 10
Aug. 27
Aug. 9
Oct. 1
July 17
July 23
Aug. 14
July 22
Aug. 18
July 14
Dec. 21
Dec. 18
Oct. 3
Dec. 27
July 21
Aug. 23
Aug. 21
Aug. 19
Feb. 14
Aug. 26
July 28
Aug. 5
Aug. 11
July 24
July 30
July 29
June 27
Aug. 7
Aug. 6
July 26
Aug. 2
Aug. 25
Oct. 2
Sept. 29
Aug. 4
Nov. 21
July 12
June 28
Oct. 10
Aug. 31
Sept. 28
Aug. 17
June 30
July 19
May 23
July 31
Sept. 11
June 20
Aug. 10
Oct. 4
Sept. 30
July 6
Dec. 17
Aug. 13
Aug. 24
Nov. 20
Dec. 12
Sept. 5
July 20
July 27
June 25
Sept. 7
Dec. 22
June 26
May 24
Dec. 16
June 29
Nov. 1
June 2
June 18
Oct. 6
Aug. 3
June 24
Oct. 7
Oct. 8
Nov. 7
July 3
June 21
Oct. 17
Sept. 6
June 14
May 22
May 16
Oct. 24
Oct. 5
Oct. 11
June 16
Oct. 15
June 3
Nov. 19
May 21
June 17
Dec. 1
June 23
June 6
Nov. 14
Nov. 15
June 10
June 4
April 4
Sept. 4
June 12
May 20
Nov. 5
Dec. 15
Feb. 15
Oct. 25
Dec. 2
March 21
July 13
Nov. 8
June 19
Nov. 18
June 5
June 1
June 7
June 11
May 15
Oct. 22
Oct. 18
Oct. 14
Feb. 7
Dec. 3
Nov. 11
March 17
Oct. 9
Dec. 5
Nov. 3
June 22
March 1
Nov. 4
Nov. 17
May 17
Sept. 3
March 14
Oct. 16
May 2
Feb. 22
Oct. 28
March 7
June 9
Nov. 6
Nov. 2
June 15
Nov. 12
March 3
May 5
May 10
May 14
Oct. 20
Feb. 8
April 11
Oct. 21
Feb. 28
Jan. 24
Oct. 23
March 28
June 13
May 9
Nov. 10
Oct. 27
June 8
Jan. 10
Nov. 16
Jan. 4
May 12
Feb. 10
Feb. 11
Oct. 12
Oct. 29
March 15
Feb. 21
April 2
April 18
March 12
March 20
May 1
Sept. 2
May 19
April 25
March 4
Dec. 4
March 5
March 8
Jan. 14
Jan. 11
March 25
Feb. 25
March 22
Dec. 6
May 8
March 18
Jan. 5
April 12
Dec. 14
Dec. 10
Jan. 25
May 6
Feb. 2
Feb. 16
May 7
Feb. 18
March 10
Jan. 12
March 11
Sept. 1
Feb. 1
Oct. 26
Feb. 23
Nov. 9
Jan. 7
March 24
March 6
March 19
Jan. 6
April 16
Feb. 4
Feb. 24
May 3
Jan. 17
May 30
April 5
May 18
April 3
Feb. 12
April 17
March 27
Feb. 9
Dec. 8
April 19
April 8
March 26
Feb. 20
Jan. 18
Jan. 31
Dec. 11
April 15
April 26
April 22
March 29
Jan. 23
April 23
April 7
Feb. 27
Nov. 30
Dec. 13
Feb. 17
Oct. 19
Dec. 9
April 24
Jan. 26
Feb. 3
Jan. 28
April 9
May 25
April 10
Jan. 20
Jan. 21
Jan. 27
April 21
Oct. 30
Jan. 3
April 14
April 28
March 2
May 28
Feb. 6
May 29
March 31
March 16
Oct. 13
March 9
Nov. 29
Jan. 30
May 11
Nov. 13
Dec. 7
March 23
April 29
April 30
Feb. 26
May 31
May 4
April 20
March 30
May 13
May 27
Jan. 19
Feb. 5
Jan. 22
Feb. 19
April 27
Nov. 22
March 13
April 6
Jan. 9
Jan.16
Jan. 13
Jan. 8
Feb. 13
Jan. 29
Jan. 15
July 5
May 26
Dec. 31
April 13
Dec. 23
April 1
Nov. 28
Nov. 26
Nov. 24
Oct. 31
Nov. 25
Nov. 23
Nov. 27
Dec. 26
Jan. 2
July 4
Dec. 24
Jan. 1
Dec. 25
Feb. 29
Birthday freebies: Score these items from your favorite stores
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This article originally appeared on USA TODAY: What is the most common birthday? These celebrities were born on it.
