In general, there are a few ways to determine your conception date. No method is 100% accurate, but some are more reliable than others. The first way to find out your conception date is to determine when you were last ovulating.

Could conception dates be wrong?

Knowing the exact day of conception is a difficult thing. Sperm can live in a womans body for up to five days, making it impossible to calculate exactly when conception occurred. It is not a fine science. In addition, women ovulate anywhere from 11 to 21 days after the first day of their last period.