EDD Due Date Calculator
Choose your preferred method and enter your date to estimate your expected due date (EDD).
This tool is for educational use only and does not replace professional medical advice.
What is an EDD due date?
EDD stands for Estimated Date of Delivery. It is the date a pregnancy is expected to reach 40 weeks. Most people call this the “due date,” but it is best thought of as a target window, not a guaranteed day.
A normal full-term birth can happen before or after that estimate. Many babies arrive between 37 and 42 weeks, which is why a due date calculator is most useful for planning prenatal milestones, appointments, and preparation.
How this EDD due date calculator works
The calculator above provides three common medical approaches:
- LMP method: Adds 280 days (40 weeks) to the first day of your last menstrual period, with cycle-length adjustment.
- Conception method: Adds 266 days (38 weeks) to the conception date.
- IVF method: Uses transfer date plus embryo age to calculate an equivalent gestational timeline.
In addition to estimated due date, the calculator shows current gestational age and useful timeline markers like trimester transitions and full-term status.
Why your due date can change
Even with careful calculations, a provider may adjust the EDD after early ultrasound data. This is common and usually reflects more precise fetal measurements in the first trimester.
Common reasons for due date updates
- Uncertain or irregular menstrual cycles
- Late ovulation compared with a 28-day cycle assumption
- Early ultrasound showing a different gestational age
- Limited certainty of conception timing
How to use your estimated due date
Your EDD can help you map key preparation tasks:
- Schedule prenatal visits and anatomy scans
- Plan work leave and childcare logistics
- Track trimester goals for nutrition, movement, and rest
- Set reminders for classes, hospital bag packing, and birth preferences
Think of the date as an anchor point for planning rather than a countdown to one exact day.
Trimester overview at a glance
First trimester (weeks 1–13)
Early development is rapid. Fatigue, nausea, and breast tenderness are common. Prenatal vitamins, hydration, and early prenatal care are especially important here.
Second trimester (weeks 14–27)
Many people feel more energetic. Anatomy scans and growth assessments usually happen in this period. You may begin to feel regular fetal movement.
Third trimester (weeks 28–40+)
Focus shifts to monitoring growth, movement patterns, and labor preparation. It is also a good time to finalize postpartum support plans.
Frequently asked questions
Is the due date exact?
No. It is an estimate. Only a small percentage of births happen exactly on the calculated date.
Which method is most accurate?
If cycles are regular and LMP is known, the LMP method is useful. In many cases, first-trimester ultrasound dating is considered the most accurate clinical reference.
Can I use this calculator for irregular cycles?
Yes, but results may vary. For irregular cycles, using conception date (if known) or discussing dating ultrasound with your provider may give better precision.
Important reminder
This EDD due date calculator is informational and should not be used for diagnosis or medical decision-making. Always consult your obstetrician, midwife, or qualified healthcare professional for personalized care.