Conception Calculator

Counting backwards from a due date, or forwards from a last period, gives an approximate conception date. Enter a due date or an actual birth date and the tool subtracts the standard 266 day gestation to place conception, then shows a five day window on either side. The second mode starts from the first day of your last period, adjusts for your cycle length to find ovulation, and returns the due date as well. Cycles vary, so the window matters far more than the single date.