How many birthdays are in 1 day?

If you assum that people's birthdays are basically random and equally spread over the entire calendar, and each day out of the 365 in a year has the same number of birthdays for it, then just take the world's population and divide by 365. That's your answer for how many people share the same birthday. (P.S. that wont be exactly accurate because some months are known for higher births than other months).