Because doctors use LMP to set a 40 week due date, we get 2 free weeks. (approx 14 days between period starting and ovulation)we are actually pregnant for only 38 weeks! Your app is telling u that day 1 (or 2 weeks before u ovulated) is July 15. But according to your due date, you probably conceived closer to the 29th. Like PP said, its hard to guess conception accurately because we can't see or feel it; we can only know when all the requirements for conception were available. ie: egg, sperm, fertile cm.
So when would my ovulation days be then? My period ran from July 5th to 15th..
your due date is based off the first day of your last period not off conception date. you ovulate for about 2-3 days every menstrual cycle. you can get an estimate of what days you could have convinced but the only way to know for sure would be if you knew what day you had sex in those fertile days. for example I was fertile Sept 30- Oct 4. but my ovulation date was on the 4th. We did the the do on Sept 28th and again Oct 3rd. based off my calendar we convinced the 3rd of Oct. I use those period apps that track your period, fertile days, ovulation day, and it lets you keep track of intimacy. Which I did very thoroughly. That's the only reason I can take a strong shot at Oct 3rd. but doesn't mean that even that is 100% accurate