Want to find out a person's conception date? You could calculate your own (yuck!), but it's also useful for calculating the conception date of your own offspring, or even your predecessors (not yuck).
Conception Date Calculator estimates the date of conception based on the due date with the credible 'Naegele's rule' (yeah, me either). But you can leave the boring equations to the app and find out the date by just inputting the baby's due date.
The app was $1 and is now FREE, so what are you waiting for?