I had sexual intercourse on jan 4th and again on jan 21.I soon was pregnant and the doctors gave me a due date for the 11th of October then a second one for the 15th of oct but my baby was born oct 14th.I'm trying to figure out which was of the days either jan 4th or jan 21st did I actually get pregnant on.

Calculations for due dates or conceptions dates is not an exact science. Nor is the gestational period exact. So I doubt if you can know for sure.

So why is this important? I'm guessing it might be because you had two different partners on those dates. If so, the only way to confirm paternity is with a paternity test.

The two dates for having sex are too close together to know which case. Due dates are merely educated guesses. So it could be either date. Unless it was different partners it really does not matter. If it is different partners you will have to just wait and have a DNA test done.