Due Date December 24: When Did You Conceive?
A due date of December 24 points back to a conception date of about April 2. Below you'll find the full set of dates that go with it, from your estimated last period to the start of each trimester.
Key dates for a December 24 due date
| Most likely conception date | April 2 |
|---|---|
| Likely conception window | March 30 – April 5 |
| Days when sex could have led to pregnancy | March 28 – April 3 |
| Estimated first day of last period | March 19 |
| Positive home test likely from | April 16 (around the missed period) |
| Second trimester begins (14 weeks) | June 25 |
| Third trimester begins (28 weeks) | October 1 |
| Full term begins (39 weeks) | December 17 |
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 December 24 gives April 2.
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?
A due date is a planning estimate rather than a promise. Most babies arrive within two weeks either side of it, which is why any conception date calculated from it is a best guess.
If your cycles are usually longer than 28 days, conception probably happened a little later than April 2; 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.