Calculate your Estimated Due Date (EDD) and track your important pregnancy milestones.
Finding out you are pregnant is an incredibly exciting moment, and the very next question is always: "When is my baby due?" Our Pregnancy Due Date Calculator uses standard medical formulas to help you estimate your baby's arrival.
Most pregnancies last around 40 weeks (280 days). Because it is very difficult to know the exact day of ovulation or conception, healthcare providers standardly calculate your due date starting from the first day of your Last Menstrual Period (LMP). Our calculator uses a modified version of Naegele's Rule, which automatically adjusts the 280-day baseline if your menstrual cycle is shorter or longer than the average 28 days.
If you were tracking your ovulation closely, using an ovulation test kit, or underwent IVF, you might know your exact conception date. In this case, simply select "Known Date of Conception" in the calculator above, and it will add exactly 266 days (38 weeks) to find your due date.
Your EDD is just an educated estimate. Only about 4% to 5% of babies are actually born exactly on their calculated due date. A pregnancy is considered full-term anywhere between 37 weeks and 42 weeks, giving your baby a 5-week window where they might naturally decide to make their appearance!
This is one of the most confusing parts of pregnancy dating! Because the medical standard starts counting from the first day of your Last Menstrual Period (LMP), "Week 1" and "Week 2" of your pregnancy are actually the weeks your body was preparing to ovulate. By the time you actually conceive, you are technically already 2 weeks pregnant according to your doctor's chart.
It can. When you go in for your first-trimester dating ultrasound (usually around 8 to 12 weeks), the technician will measure the crown-to-rump length of the fetus. If the ultrasound measurement suggests a due date that is more than a few days different from your LMP calculation, your doctor will likely update your official due date based on the ultrasound, as early fetal growth is highly predictable.