# Same birthday probability Calculator

## Calculates the probability that one or more pairs in a group have the same birthday.

 n personsin a group 6digit10digit14digit18digit22digit26digit30digit34digit38digit42digit46digit50digit Probability with same birthdays p(n) %
(1) the probability that all birthdays of n persons are different.

(2) the probability that one or more pairs have the same birthday.

This calculation ignores the existence of leap years.
Same birthday probability
 [1-2] /2 Disp-Num5103050100200
[1]  2017/12/04 21:36   40 years old level / Others / A little /
Purpose of use
Settling an argument.
Comment/Request
In a random sample of "n" people, 2 are found to share the same birthday.
In a second random sample of people, 2 are found to share the same birthday.
What are the odds that both pairs of people share the same birthday?
[2]  2009/07/29 17:00   More than 60 / Others / Very /
Purpose of use
Very useful for backing up a bet taken in a pub. Thank you - I won.
Comment/Request
I love this kind of "dispute" settler - in addition, the formulae are beautifully complex in appearance, so my non-maths friends are entirely bamboozled.

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