Due date from conception date calculator
Useful if you track ovulation with tests or know the conception day, since counting from it does not depend on cycle length.
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Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter conception or ovulation date.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Due date = conception date + 266 days. Equivalent last period = conception - 14 days; the second trimester starts 98 days after it and the third 196 days after it.
Example
Inputs: Conception or ovulation date = 2026-01-15. Result: Estimated due date: Thursday, October 8, 2026 (2026-10-08); Equivalent last period date: Thursday, January 1, 2026 (2026-01-01); Second trimester starts: Thursday, April 9, 2026 (2026-04-09).
Limits and caveats
- It assumes an average pregnancy length; birth can come two weeks before or after.
- For IVF use the IVF due date calculator instead.
Questions about this tool
Is ovulation day the same as conception day?
Nearly. The egg lives about 12 to 24 hours after release, so fertilization happens on ovulation day or the next.
Why does my doctor give a different date?
Your doctor may date the pregnancy from an ultrasound measurement, which is more precise than an estimated conception day.
How long is pregnancy from conception?
About 266 days on average, which is 38 weeks.