I am trying to figure out the date of sex that led to me getting pregnant. my due date is aug 4, 2017.

Only 2 people know: Generally, only the two people having sex know when they had sex. Pregnancy dating in a natural pregnancy is always an estimate. The estimated due date is 38 weeks after the estimated conception date. Thus, one can grab a calendar and count backwards 38 weeks from August 4th. That day, 38 weeks before August 4th, is the estimated conception date, plus or minus one week.