Due Date February 21: When Did You Conceive?
Wondering when your February 21 baby was conceived? Using the standard 266-day rule, the answer is most likely May 31 of the previous year, give or take a few days.
Key dates for a February 21 due date
| Most likely conception date | May 31 |
|---|---|
| Likely conception window | May 28 – June 3 |
| Days when sex could have led to pregnancy | May 26 – June 1 |
| Estimated first day of last period | May 17 |
| Positive home test likely from | June 14 (around the missed period) |
| Second trimester begins (14 weeks) | August 23 |
| Third trimester begins (28 weeks) | November 29 |
| Full term begins (39 weeks) | February 14 |
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 February 21 gives May 31.
Sperm can survive in the reproductive tract for up to five days, while an egg lives for about 12 to 24 hours after ovulation. That means sex several days before ovulation can still lead to pregnancy.
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 May 31; 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.