Estimate your likely conception date based on either your last menstrual period or your due date.
This tool estimates the approximate date of conception based on standard pregnancy timing assumptions.
Conception is estimated as 14 days after the start of the last menstrual period, or 266 days before the due date, assuming a typical 28 day cycle.
Select whether you know your last period date or your due date, enter it, and click Calculate.
Example: If your last period started on a given date, conception is typically estimated 14 days later, around the time of ovulation.
How accurate is this estimate. It is an approximation based on average cycles; actual conception timing varies between individuals.
Why does cycle length matter. Ovulation timing shifts with cycle length, so irregular cycles make this estimate less precise.