when do i ovulate on a 28 day cycle
Ovulation happens approximately 13 days after menstruation starts. In a 28 day cycle, the moment of menstruation is usually counted as day one. Here is a link menses cycle: http://www.ask.com/wiki/Menstrual_cycle
If you have a 28 day cycle, you most likely ovulate around day 14. Most women ovulate right in the middle of their cycle.
All women are a little different, so there is no exact answer. With a 28 day cycle, you will likely ovulate on day 14.