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Conceived in December: when is the baby due?

A baby conceived in December is due between 24 August and 23 September of the following year.

That is 38 weeks (266 days) after conception: a pregnancy is counted as 40 weeks from the first day of the last period, about two weeks before conception.

Calculate from
days

Usually 28 days. Count from the first day of one period to the first day of the next.

Calculated on your device. Nothing is sent.

Estimated due date

Enter a date to see your estimated due date.

Not medical advice. Every pregnancy is different: ask your midwife or doctor about yours.

Due date for each day in December

Due date for a conception on each day in December
ConceptionDue date
1 December24 August
2 December25 August
3 December26 August
4 December27 August
5 December28 August
6 December29 August
7 December30 August
8 December31 August
9 December1 September
10 December2 September
11 December3 September
12 December4 September
13 December5 September
14 December6 September
15 December7 September
16 December8 September
17 December9 September
18 December10 September
19 December11 September
20 December12 September
21 December13 September
22 December14 September
23 December15 September
24 December16 September
25 December17 September
26 December18 September
27 December19 September
28 December20 September
29 December21 September
30 December22 September
31 December23 September

In a leap year, the date moves by one day when 29 February falls between conception and the due date.

Frequently asked questions

If we conceived in December, when is the baby due?

A baby conceived in December is due between 24 August and 23 September of the following year. The table on this page gives the due date for each day of conception, and the calculator works it out from your own date.

Why is the due date 40 weeks if the baby was conceived 38 weeks before?

Pregnancy is counted from the first day of the last period, about two weeks before ovulation and conception. So the 40 weeks include two weeks before the baby was conceived.

Will the baby come on the due date?

Probably not exactly. Only about 4% of babies are born on their due date, and most arrive in the two weeks before or after it. An early scan gives the most reliable date.