Conception Date Calculator
Curious when conception likely happened? Work backwards from a due date or your baby's birth date to estimate the date, and the window around it.
Work it out from…
Estimated conception date
Conception most likely happened between and .
The dates behind it
| Conception window opens | |
| Most likely conception | |
| Conception window closes | |
| Approx. last period before |
This assumes a typical 40-week pregnancy. Conception is counted about two weeks after the last period, which is why the dates line up this way.