The chance of: two people sharing a birthday would be 1 - (364/365), or 0.3%, or 1 in 370.
How common is it to share a 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. So how many people would you have to gather together in a room to ensure at least a 50% chance that two people in the room share a birthday?
What is the probability that two friends will have same birthday?
Let's start simple. What's the chance that two people share the same birthday? The first person can be born on any day of the year, this means that the probability is 365/365 = 1. The second person has to be born on the same day as the first and there is a 1/365 chance of that happening.
What are the odds of sharing a birthday with someone in a room?
In a room of just 23 people there's a 50-50 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.
What is the rarest birthday?
Christmas Day
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 is the probability that two friends have same birthday?
What's the chance that two people share the same birthday? The first person can be born on any day of the year, this means that the probability is 365/365 = 1. The second person has to be born on the same day as the first and there is a 1/365 chance of that happening.
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.
Frequently Asked Questions
How do you calculate the probability of sharing a birthday?
What's the chance that two people share the same birthday? The first person can be born on any day of the year, this means that the probability is 365/365 = 1. The second person has to be born on the same day as the first and there is a 1/365 chance of that happening.
What is the birthday room theory?
We are all players in the Birthday Paradox
If there are 23 people in the same room, there is a 50/50 chance that two people have the same birthday. Sounds a bit surprising, but it's mathematically true! In a room with a certain number of randomly chosen people, a pair of them will probably be born on the same day.
What are the odds 2 people share a birthday?
Theoretically, the chances of two people having the same birthday are 1 in 365 (not accounting for leap years and the uneven distribution of birthdays across the year), and so odds are you'll only meet a handful of people in your life who enjoy the same birthday as you.
FAQ
- How many people in a group to have two with the same birthday?
- 23 people. In a room of just 23 people there's a 50-50 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, counter-intuitive, and completely true.
- What is the 23 birthday paradox?
- 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.
- 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 are the odds that two people share the same birthday
How likely is it to share a birthday? | Clinical bottom line. With 40 people in a room, there is a 90% chance that any two will share a birthday. Even with 365 people in a room, there is only a chance of just below 1 in 2 that any two will share a particular birthday. |
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. |
How likely do you think it is that you share a birthday with one of your classmates? | So, the probability that at least one of your classmates has the same birthday as you is about 6.9%. |
- 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%.
- Do soulmates have the same birthday?
- Despite the appeal of finding someone born on the exact same day, the idea that all soulmates or twin flames share a birthday is myth, not fact. Plenty of fulfilling relationships happen between people with different birthdays. And many same-birthday couples don't necessarily have that “cosmic” connection.