Estimated Delivery Date
The date your baby is estimated to arrive - also called your due date - and how far along you are today, from your last period, conception date, or IVF transfer.
Calculate from
Key milestones
| Milestone | Week | Date |
|---|
Estimated delivery date
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Enter a date to begin
You are
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pregnant today
Trimester
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Days to go
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Conceived around
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approximate
Your pregnancy timeline
Progress bar across three trimesters
Week 0
Week 13
Week 27
Week 40
1st trimester
Weeks 1-13
2nd trimester
Weeks 14-27
3rd trimester
Weeks 28-40
Only about 1 in 20 babies arrives on the estimated date. Term birth spans 37-42 weeks - treat it as a range, not a deadline.
An estimate, not a diagnosis. A first-trimester scan beats any calendar calculation. If your scan date differs, go with your doctor's.
Frequently asked questions
How is a due date calculated?
The standard method, Naegele's rule, adds 280 days (40 weeks) to the first day of your last menstrual period. This calculator also adjusts for cycle length - if your cycle runs 32 days rather than 28, ovulation happened later and the estimate shifts accordingly.
Why count from my last period when I wasn't pregnant then?
Because it is a date you can actually identify. The exact moment of conception usually isn't known. The consequence is that the first two weeks of a "40-week" pregnancy happen before conception - which is why you are considered "4 weeks pregnant" about two weeks after conception.
How accurate is the estimated due date?
Roughly 1 in 20 babies arrives on the exact date. A normal term birth is anywhere from 37 to 42 weeks. Early ultrasound dating is more accurate than calendar dating, particularly if your cycles are irregular.
How do I calculate a due date after IVF?
From the transfer date, accounting for embryo age. A day-5 blastocyst transfer gives a due date 261 days later; a day-3 embryo transfer gives 263 days. Select the matching option above.
What if my scan gives a different date?
Follow the scan. First-trimester ultrasound measurement is the most reliable dating method, and clinicians will usually re-date the pregnancy if the scan differs from your dates by more than about a week.