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