When is your baby due?
Enter the first day of your last menstrual period or your conception date and get your estimated due date instantly, along with your current week of pregnancy, trimester, days remaining and the key dates on your pregnancy timeline.
Your dates
Choose whether you are entering your LMP or conception date.
Enter the conception date or first day of your last menstrual period.
The LMP method adds 280 days (40 weeks) to the first day of your last period, following Naegele's rule. The conception method adds 266 days (38 weeks) to the conception date. Results update as you type.
What your due date means
Where you are on the pregnancy timeline
Milestone dates for your pregnancy
Key weeks and typical checkups
Every row is calculated from the date you entered. The highlighted row is the closest to where you are right now.
| Week | Approx. date | What typically happens |
|---|
Due date estimation, explained
How Due Dates Are Estimated
Due dates are estimated using two common methods. The LMP method adds 280 days (40 weeks) to the first day of your last menstrual period, following Naegele's rule. The conception method adds 266 days (38 weeks) to the estimated conception date. Both methods assume a 28-day cycle and ovulation on day 14. Only about 5% of babies are born on their exact due date.
Understanding Pregnancy Weeks and Trimesters
Pregnancy is divided into three trimesters. The first trimester spans weeks 1-12 and involves critical organ development. The second trimester (weeks 13-26) brings visible growth and is often the most comfortable period. The third trimester (weeks 27-40) focuses on fetal weight gain and final development before birth.
Common questions
Which method is more accurate, LMP or conception date?
If you know the exact conception date, that method is more accurate since it eliminates the assumption about when ovulation occurred. However, most women know their LMP date more reliably. An early ultrasound (before 12 weeks) provides the most accurate dating.
What if I don't know my exact conception date?
Most women use the LMP method. If your cycles are irregular, or you are unsure of your LMP date, an early ultrasound is the best way to establish a due date. The dating ultrasound measures the embryo to estimate gestational age.
How accurate is the due date?
Due dates are estimates within a two-week window. Only 5% of babies arrive on their exact due date, and most births occur between 38 and 42 weeks. A baby is considered full term between 39 and 40 weeks.
This calculator gives an estimate, not a medical diagnosis. Only about 5% of babies arrive on their exact due date, and date-based estimates can be off by two weeks or more, especially with irregular cycles. An early ultrasound (before 12 weeks) is the most accurate way to date a pregnancy, and your exact due date is determined by your gynecologist or obstetrician. Always follow the guidance of your prenatal care provider, and seek immediate care for heavy bleeding, severe pain or decreased fetal movement.