If you want to know the odds of being born on a particular day, they are 365:1, or 366:1 in a leap year. If you want to know the odds of two people having the same birthday meeting each other, they are roughly 207 million to one.
What are the odds two people meet?
What are the odds of 2 random people in the world meeting? Apparently people meet about 80,000 people on average in their lifetime. So if there are 8 billion people in the world then the odds of meeting a specific other person are about 80,000/8,000,000,000 which is one in a hundred thousand, or a 0.001% chance.
What is the probability of 2 people not sharing the same birthday?
The probability that a person does not have the same birthday as another person is 364 divided by 365 because there are 364 days that are not a person's birthday. This means that any two people have a 364/365, or 99.726027 percent, chance of not matching birthdays.
Is the birthday paradox true?
The birthday paradox refers to the counterintuitive fact that only 23 people are needed for that probability to exceed 50%. The birthday paradox is a veridical paradox: it seems wrong at first glance but is, in fact, true.
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.
What are the odds of 2 people having the same birthday?
The chance of: two people sharing a birthday would be 1  (364/365), or 0.3%, or 1 in 370.
How many people are likely to have the same birthday?
In a room of just 23 people there's a 5050 chance of at least two people having the same birthday. In a room of 75 there's a 99.9% chance of at least two people matching. Put down the calculator and pitchfork, I don't speak heresy. The birthday paradox is strange, counterintuitive, and completely true.
Frequently Asked Questions
What are the odds of 2 people out of 30 having the same birthday?
The probability of sharing a birthday = 1 − 0.294... = 0.706... Or a 70.6% chance, which is likely! So the probability for 30 people is about 70%.
What is the probability of two persons being born on the same day?
The chance that the second person has the same birthday is 1/365 or about 0.27%.
What is the probability that two persons among n have same birthday?
The probability that in a group of N people at least two will have the same birthday is. 1−(365)! (365)N(365−N)!
What are the odds of dating two people with the same birthday?
If you have only 2 girlfriends then the chances they share the same birthday (the same day and the same month but not necessarily the same year) is 1/365 = approximately 0.27%.
What are the odds of sharing a birthday in a group?
23 people. In a room of just 23 people there's a 5050 chance of at least two people having the same birthday. In a room of 75 there's a 99.9% chance of at least two people matching.
FAQ
 What percent is the probability of a shared birthday within a group of 23 people?
 A 50 percent You can test it and see mathematical probability in action! The birthday paradox, also known as the birthday problem, states that in a random group of 23 people, there is about a 50 percent chance that two people have the same birthday.
 How many people in a group have the same birthday?
 23 people In probability theory, the birthday problem asks for the probability that, in a set of n randomly chosen people, at least two will share a birthday. The birthday paradox refers to the counterintuitive fact that only 23 people are needed for that probability to exceed 50%.
 What is the probability that 2 randomly chosen people share a birthday?
 In Blitzstein's Introduction to Probability, it is stated that the probability that any two people have the same birthday is 1/365.
 What's 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.
What are the odds that you have the same birthday as someone
What is the probability of having a birthday in the same month?  The probability of the birthdays being in the same month is 1/12 (or, 1 – 11/12).  
What is the probability of two people having the same birth month?  Hence, the correct option is B) 1/12. Explanation: The probability of two friends sharing the same birth month is 1/12 because there are 12 possible birth months, and only one of those months will match the other friend's birth month. The probability is independent of the order in which the friends were born.  
Is birthday paradox true?  The birthday paradox refers to the counterintuitive fact that only 23 people are needed for that probability to exceed 50%. The birthday paradox is a veridical paradox: it seems wrong at first glance but is, in fact, true.  
What are the odds of 30 people having the same birthday?  Table: Chance of two people sharing a birthday

 What is the rarest birthday date?
 December 25 (Christmas Day) is the least common birthday, while January 1 (New Year's Day) is the second least common. December 24 (Christmas Eve) also makes the list as the 3rd least common birthday while July 4 (Independence Day) is the 4th least common birthday.
 What are the odds to find someone with the same birthday?
 The odds are 1/366, or 0.0027%! And those aren't very good odds. That's why when you meet someone who has the same birthday as you, it always seems like a neat coincidence.
 How common is it for someone to have the same birthday as you?
 Originally Answered: what is the probability of having the same birthday as someone? It's easy to say that the answer is 1 in 365 because there are 365 days in a year (usually).
 What is the 99 chance of having the same birthday?
 In a room of just 23 people there's a 5050 chance of at least two people having the same birthday. In a room of 75 there's a 99.9% chance of at least two people matching. Put down the calculator and pitchfork, I don't speak heresy. The birthday paradox is strange, counterintuitive, and completely true.