Pregnancy Due Date Calculator
Quickly calculate your expected delivery date and track your pregnancy timeline.
When is your baby due? Use this pregnancy calculator to find your due date based on the date of your last menstrual period, conception date, IVF three-day or five-day transfer date, or date of your last ultrasound.
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What is an Estimated Due Date (EDD)?
An estimated due date (EDD) is the date when your baby is expected to be born. It is usually 40 weeks (280 days) from the first day of your last menstrual period. Only about 5% of babies are born on their exact due date, but most arrive within a two-week window on either side.
How is Due Date Calculated?
1. From the Last Menstrual Period (LMP)
The most common method is Naegele’s rule:
- Take the first day of your last menstrual period
- Add 1 year
- Subtract 3 months
- Add 7 days
This assumes a 28-day cycle. Adjustments may be made for shorter or longer cycles.
2. From Conception Date
If you know the exact conception date, add 266 days (38 weeks). This can be more accurate, especially if you were tracking ovulation or used assisted reproduction.
3. For IVF Pregnancies
Because embryo transfer dates are exact, IVF due dates are calculated as:
- 3-day transfer → add 263 days
- 5-day transfer → add 261 days
4. Using Ultrasound Scans
Ultrasounds (especially in the first trimester) can estimate gestational age by measuring crown-rump length or other growth markers. If ultrasound results differ significantly from LMP dates, doctors may adjust your due date.
Can My Due Date Change?
Yes. Your provider may revise it if:
- You have irregular cycles
- The LMP date is uncertain
- Early ultrasound results differ significantly
- Multiple pregnancies are discovered
Once confirmed by an early ultrasound, due dates usually remain unchanged.
Can I Plan My Due Date?
It’s possible to plan the season of birth by timing conception, but exact dates are unpredictable. Ovulation timing, sperm survival, implantation, and natural variation in pregnancy all play a role. The only way to guarantee a specific date is through a medically scheduled induction or cesarean section.
What Happens in Each Trimester?
First Trimester (Weeks 1–12)
- Major organs and systems form
- Heart begins beating around week 6
- Morning sickness, fatigue, mood swings common
Second Trimester (Weeks 13–26)
- Baby’s movements (“quickening”) felt
- Gender may be visible on ultrasound
- Energy levels often improve
Third Trimester (Weeks 27–40)
- Baby gains weight rapidly
- Brain and lung development continue
- Baby usually moves head-down
- Mother may feel more discomfort, Braxton Hicks, sleep issues
How You Can Use This Information
- Track pregnancy milestones
- Schedule prenatal checkups and tests
- Prepare for your baby’s arrival with more confidence