It is really different for everyone. The "typical" cycle is 28 days and you ovulate halfway through on CD 14. you only ovulate one day. sperm can live in your body up to 5 days. You really need to look for your body's signs as to when you're ovulating. You can check your cervical mucas and BBT. The easiest thing to do is to her an OPK and test for ovulation that way.