Birthday Twins – Meaning, Odds, and the Birthday Paradox

Pop quiz!

What is a birthday twin?

  1. Someone who is celebrating their birthday on the same day as you are.
  2. A person who dresses like you do on your birthday.
  3. Anyone who shares the same birth month and day.

What is a birthday twin? A birthday twin is anyone who shares the same birth month and day. For example, Abraham Lincoln’s birthday was February 12th, 1809. If your birthday is also on February 12, then you are birthday twins with Abraham Lincoln. You do not need to share the same year to be a birthday twin.

Have you ever tried to get a dinner reservation for your birthday, only to find out that your favorite restaurant is full? Perhaps it was your birthday twin who got there before you did. 

Birthday Twins

Other names for birthday twins are cosmic twins, birthday mate, and birthday fellow.

Birthday Twin Meaning

Birthday twins are people who were born on the same day and in the same month. There are other cool birthday connections out there, such as birthdate twins. 

But in that case, you would need to not only be born on the same day and in the same month, but also in the same year. 

What Are the Odds of Someone Having the Same Birthday as You?

Logically, our brains would like to think: If I am in a room with 22 other people, and there are 365 days in a year, then it is not likely any of us will have been born on the same day and in the same month. 

However, our brains are a little self-centered. They only think about us, because hey…. aren’t we talking about our birthdays here? We tend to forget that we’re not just matching up 22 birthdays to our own. 

We are actually making 253 comparisons when we include everyone else. There are also other factors to be considered like being born on February 29 during a leap year or if you happen to be born during the summer. 

In the United States, it is more likely for a person to be born in the month of August. 

How Many People Share My Birthday?

Strictly by the numbers, you share your birthday with well over 20 million people worldwide. 

What Is the Birthday Paradox?

The birthday paradox is a question that begs one to wonder just how many people will be blowing out their candles on the same day that you do. It’s like a surprise birthday party; it is not what we were expecting, it’s a lot more, and it’s not really a paradox. 

The key is recognizing that we are looking for pairs of matching birthdates. 

Related Questions:

Is It Rare for Siblings To Have the Same Birthday?

It is not common for siblings to have the same birthday unless you are a twin. The chances are that two non-twin siblings will have the same birthday is 1 in 50,000. The chances of having twins are 1 in 250. You have a better chance of having a twin than you do sharing a birthday with a sibling. 

What Is a Time Twin?

A time twin is another name for a birthdate twin. You must be born in the same year, in the same month, and on the same day to be called a time twin.