If you're trying to estimate when your baby may arrive, this delivery due date calculator gives you a fast, practical starting point. You can calculate your estimated due date using your last menstrual period (LMP), conception date, or IVF transfer date.
Pregnancy Delivery Due Date Calculator
This tool provides an estimate only. Your healthcare provider may adjust your due date based on ultrasound and clinical findings.
What is a delivery due date?
Your delivery due date, often called the estimated due date (EDD), is the date when your pregnancy reaches 40 weeks of gestation. It is an estimate, not a deadline. Most babies are born within a window around this date rather than on the exact day.
In a typical pregnancy, labor can naturally begin any time between 37 and 42 weeks. So think of your due date as a useful planning marker for prenatal visits, leave planning, and birth preparation.
How this calculator works
1) Last menstrual period (LMP) method
This is the most common way to estimate a due date. It assumes a 28-day cycle and ovulation around day 14, then adjusts when cycle length differs. Standard formula:
- Add 280 days (40 weeks) to the first day of your LMP
- Adjust by cycle length difference from 28 days
2) Conception date method
If you know your conception date reasonably well, the calculator adds 266 days (38 weeks). This can be useful if ovulation and conception timing are clear.
3) IVF transfer method
For IVF pregnancies, due date estimates can be more precise because transfer date and embryo age are known. The calculator adds days based on the embryo age at transfer.
Why due dates can change
Even with accurate data, due dates can shift. Early ultrasound is often used to refine dating, especially when menstrual cycles are irregular or LMP is uncertain. Your provider may update your EDD after reviewing fetal measurements.
- Irregular cycle timing
- Uncertain LMP recollection
- Late ovulation or implantation
- Dating differences between LMP and ultrasound
Understanding your results
After you calculate, you'll see more than just a due date. You also get:
- Estimated gestational age (weeks + days)
- Trimester estimate
- Time remaining until due date (or days overdue)
- Full-term window (approximately 37 to 42 weeks)
These values are practical for planning checkups, classes, travel limits, and home preparation milestones.
Practical planning checklist by stage
First trimester
- Schedule initial prenatal care and lab work
- Review medications and supplements with your provider
- Start tracking symptoms, hydration, and rest
Second trimester
- Complete anatomy scan and routine screenings
- Begin budgeting for delivery and newborn essentials
- Discuss maternity/paternity leave timelines
Third trimester
- Pack your hospital bag early
- Install and test infant car seat
- Finalize pediatrician and postpartum support plans
Frequently asked questions
Is the due date exact?
No. It is an estimate. A healthy full-term birth can occur before or after the estimated date.
What if my cycle is longer than 28 days?
Use the LMP method and enter your average cycle length. Longer cycles often move the estimate slightly later; shorter cycles can move it earlier.
Can I use this calculator for IVF?
Yes. Select IVF transfer date and choose embryo age. This method often provides a strong initial estimate.