The Conception Calculator

Conceived on Christmas Day? Here's the Due Date

Due dates & conception. Updated . Calculated with the standard pregnancy dating method used by ACOG and the NHS.

If conception happened on Christmas Day (December 25), the baby would be due around September 17 the following year.

Conception dateDecember 25
Estimated due dateSeptember 17
Likely due window (37–42 weeks)August 27 – October 1
Last period probably startedDecember 11

Remember that sex and conception aren't always on the same day: sperm can survive for up to five days, so a holiday celebration could lead to conception a few days later.

Check your own dates with the due date calculator.

Due Date Calculator: Estimate your due date from the first day of your last period.

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This article is general information, not medical advice. Talk to a doctor or midwife about your own pregnancy or fertility.