When Did I Conceive if My Due Date Is June 17?
Wondering when your June 17 baby was conceived? Using the standard 266-day rule, the answer is most likely September 24 of the previous year, give or take a few days.
Key dates for a June 17 due date
| Most likely conception date | September 24 |
|---|---|
| Likely conception window | September 21 – September 27 |
| Days when sex could have led to pregnancy | September 19 – September 25 |
| Estimated first day of last period | September 10 |
| Positive home test likely from | October 8 (around the missed period) |
| Second trimester begins (14 weeks) | December 17 |
| Third trimester begins (28 weeks) | March 25 |
| Full term begins (39 weeks) | June 10 |
How the conception date is calculated
Due dates are normally counted as 280 days (40 weeks) from the first day of the last menstrual period. In a typical 28-day cycle, ovulation and conception happen about two weeks after that period starts, so conception sits roughly 266 days before the due date. Subtracting 266 days from June 17 gives September 24.
Conception happens when sperm meets the egg, usually within a day of ovulation. Since sperm may wait up to five days for an egg to be released, the window for sex that could have caused the pregnancy is wider than a single day.
How certain is this date?
Remember that a due date is only the midpoint of a range. Ovulation timing varies from cycle to cycle, so the true conception day can sit a few days away from the estimate.
If your cycles are usually longer than 28 days, conception probably happened a little later than September 24; with shorter cycles, a little earlier. A cycle that is 32 days long, for example, shifts the likely date about four days later.
Check your own dates
Enter your exact due date in the conception date calculator to see these results with weekdays and the correct year, or start from your last period with the last-period conception calculator.
Conception Date Calculator: Find the most likely conception date from your due date.
Open the calculatorThis article is general information, not medical advice. Talk to a doctor or midwife about your own pregnancy or fertility.