Knowing your likely conception date can help you understand your pregnancy timeline better, especially for medical records or curiosity about when your baby was conceived.
This calculator works backward from your due date, subtracting 266 days (38 weeks) - the average length of pregnancy counted from ovulation/conception.
Example: Due date of 8 October:
Conception ≈ 8 October - 266 days = around 15 January
280 days is counted from your last period, but conception itself typically happens about 2 weeks later, around ovulation, making the conception-to-birth span roughly 266 days.
It's an estimate assuming a typical cycle - actual conception can vary by several days depending on your individual cycle.
No, this is only a general estimate and not suitable for legal or medical paternity determinations.