# How popular is your birthday?

## More than you think, according to maths

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Happy birthday to you. And you. And you. Yes, it seems we are not as unique as we think.

Meeting someone with the same birthday as you seems like a big coincidence at the time. But it is? No, according to mathmatics.

It's called the 'birthday paradox' - the chances of two people within a random group sharing the same birthday. Given the fact that there are 366 possible birthdays - including February 29th - it doesn't seem all that likely.

But, in a room with 23 people there is actually more than a 50 per cent chance that two of those people will share the same birthday. If that seems high, consider this: in a group of 23 people there are actually 253 possible chances of a match.

Putting the theory to the test

If this maths is hard to get your head around, thankfully there is a practical experiment to illustrate the point. The guy in the video puts the birthday paradox to the test.

He says by the time he asks 23 people when their birthday is, there is a 50.7 per cent chance of a match. In the end, he only had to ask 16 people before a match presented itself.

Spooky? Why not try it yourself.