Due Date Calculator
Calculate your estimated due date, track your pregnancy week by week, and discover important milestones throughout your pregnancy journey.
Calculate Your Due Date
Choose your calculation method:
Your Pregnancy Journey
0% CompleteFirst Trimester
Weeks 1-12
--Second Trimester
Weeks 13-27
--Third Trimester
Weeks 28-40
--Important Milestones
Understanding Your Due Date
Your due date, also called your estimated date of delivery (EDD), is the date your healthcare provider thinks you will have your baby. It's important to remember that your due date is only an estimate – most babies are born within two weeks before or after the estimated due date.
Due Date Calculation Methods
Last Menstrual Period (LMP) Method
This is the most common method. It assumes you have a 28-day cycle and ovulated on day 14. The calculation adds 280 days (40 weeks) to the first day of your last menstrual period.
Conception Date Method
If you know your exact conception date (perhaps through ovulation tracking or IVF), we add 266 days (38 weeks) to that date.
IVF Transfer Method
For IVF pregnancies, we calculate based on the embryo transfer date and the age of the embryo at transfer.
What Your Due Date Means
- Full Term: 39 weeks 0 days to 40 weeks 6 days
- Early Term: 37 weeks 0 days to 38 weeks 6 days
- Late Term: 41 weeks 0 days to 41 weeks 6 days
- Postterm: 42 weeks 0 days and beyond
Frequently Asked Questions
How accurate is the due date calculator?
The calculator provides an estimate based on average cycles. Only about 5% of babies are born on their exact due date. Most babies are born within two weeks before or after the estimated due date. Ultrasound dating in the first trimester is typically the most accurate method.
Can my due date change?
Yes, your healthcare provider may adjust your due date based on ultrasound measurements, especially if done in the first trimester. Early ultrasounds are more accurate for dating than later ones.
What if I have irregular periods?
If you have irregular periods, the LMP method may be less accurate. An early ultrasound will provide a more reliable due date. You can also use the conception date if you were tracking ovulation.
Why is pregnancy counted as 40 weeks when it's only 9 months?
Pregnancy is counted from the first day of your last menstrual period, about two weeks before conception actually occurs. This makes pregnancy about 40 weeks (280 days) from LMP, or about 38 weeks (266 days) from conception. The 40 weeks equals about 9.2 months.