Due or born in December: when was the baby conceived?
A baby due in December was most likely conceived between 10 March and 9 April.
For a baby born in December at full term, from 37 to 42 weeks, conception was most likely between 24 February and 30 April.
Most likely conception date
Enter a date to see when conception most likely happened.
Not medical advice. Every pregnancy is different: ask your midwife or doctor about yours.
Conception date for each day in December
| Due date or birthday | Conception, for a due date | Conception, for a birth at 37 to 42 weeks |
|---|---|---|
| 1 December | 10 March | 24 February to 31 March |
| 2 December | 11 March | 25 February to 1 April |
| 3 December | 12 March | 26 February to 2 April |
| 4 December | 13 March | 27 February to 3 April |
| 5 December | 14 March | 28 February to 4 April |
| 6 December | 15 March | 1 March to 5 April |
| 7 December | 16 March | 2 March to 6 April |
| 8 December | 17 March | 3 March to 7 April |
| 9 December | 18 March | 4 March to 8 April |
| 10 December | 19 March | 5 March to 9 April |
| 11 December | 20 March | 6 March to 10 April |
| 12 December | 21 March | 7 March to 11 April |
| 13 December | 22 March | 8 March to 12 April |
| 14 December | 23 March | 9 March to 13 April |
| 15 December | 24 March | 10 March to 14 April |
| 16 December | 25 March | 11 March to 15 April |
| 17 December | 26 March | 12 March to 16 April |
| 18 December | 27 March | 13 March to 17 April |
| 19 December | 28 March | 14 March to 18 April |
| 20 December | 29 March | 15 March to 19 April |
| 21 December | 30 March | 16 March to 20 April |
| 22 December | 31 March | 17 March to 21 April |
| 23 December | 1 April | 18 March to 22 April |
| 24 December | 2 April | 19 March to 23 April |
| 25 December | 3 April | 20 March to 24 April |
| 26 December | 4 April | 21 March to 25 April |
| 27 December | 5 April | 22 March to 26 April |
| 28 December | 6 April | 23 March to 27 April |
| 29 December | 7 April | 24 March to 28 April |
| 30 December | 8 April | 25 March to 29 April |
| 31 December | 9 April | 26 March to 30 April |
In a leap year, the date moves by one day when 29 February falls between conception and the due date or birth.
Frequently asked questions
If our baby is due in December, when did we conceive?
A baby due in December was most likely conceived between 10 March and 9 April. That is 38 weeks (266 days) before the due date. The table on this page gives the date for each due date in the month.
Born in December: when was the baby conceived?
For a baby born in December at full term, from 37 to 42 weeks, conception was most likely between 24 February and 30 April. For a birth at exactly 40 weeks, it is the same date as for a due date that day.
Can a conception date settle a paternity question?
No. This is the textbook estimate. It cannot know your cycle, when you actually ovulated or how the pregnancy was dated, and it is not precise enough to tell apart two dates a few days apart.