Due or born in January: when was the baby conceived?
A baby due in January was most likely conceived between 10 April and 10 May of the year before.
For a baby born in January at full term, from 37 to 42 weeks, conception was most likely between 27 March and 31 May of the year before.
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 January
| Due date or birthday | Conception, for a due date | Conception, for a birth at 37 to 42 weeks |
|---|---|---|
| 1 January | 10 April | 27 March to 1 May |
| 2 January | 11 April | 28 March to 2 May |
| 3 January | 12 April | 29 March to 3 May |
| 4 January | 13 April | 30 March to 4 May |
| 5 January | 14 April | 31 March to 5 May |
| 6 January | 15 April | 1 April to 6 May |
| 7 January | 16 April | 2 April to 7 May |
| 8 January | 17 April | 3 April to 8 May |
| 9 January | 18 April | 4 April to 9 May |
| 10 January | 19 April | 5 April to 10 May |
| 11 January | 20 April | 6 April to 11 May |
| 12 January | 21 April | 7 April to 12 May |
| 13 January | 22 April | 8 April to 13 May |
| 14 January | 23 April | 9 April to 14 May |
| 15 January | 24 April | 10 April to 15 May |
| 16 January | 25 April | 11 April to 16 May |
| 17 January | 26 April | 12 April to 17 May |
| 18 January | 27 April | 13 April to 18 May |
| 19 January | 28 April | 14 April to 19 May |
| 20 January | 29 April | 15 April to 20 May |
| 21 January | 30 April | 16 April to 21 May |
| 22 January | 1 May | 17 April to 22 May |
| 23 January | 2 May | 18 April to 23 May |
| 24 January | 3 May | 19 April to 24 May |
| 25 January | 4 May | 20 April to 25 May |
| 26 January | 5 May | 21 April to 26 May |
| 27 January | 6 May | 22 April to 27 May |
| 28 January | 7 May | 23 April to 28 May |
| 29 January | 8 May | 24 April to 29 May |
| 30 January | 9 May | 25 April to 30 May |
| 31 January | 10 May | 26 April to 31 May |
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 January, when did we conceive?
A baby due in January was most likely conceived between 10 April and 10 May of the year before. 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 January: when was the baby conceived?
For a baby born in January at full term, from 37 to 42 weeks, conception was most likely between 27 March and 31 May of the year before. 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.