first off u need to know how many days are in between ur cycles everyone is different but u should start around 10 days after ur period starts(ie-cycleday10) mine is 25 days so my best day for pregnancy should be CD12. Just got to Fertilityfriend.com and put ur info in and start taking ur temperature
It depends on the length of your cycle...but generally, if you have a "normal" 28-day cycle, you'll probably ovulate between day 12 and 16. And you're most fertile in the two or three days leading up to ovulation and the day of ovulation. Hope that helps!