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Find out when your baby is due with our accurate pregnancy calculator. Calculate your due date based on your last menstrual period, conception date, or ultrasound date, and track your pregnancy week by week.
Most women have a 28-day cycle. Adjust if yours is different.
Enter your last menstrual period date to calculate your due date
Calculating your pregnancy due date is one of the first and most exciting steps of pregnancy. While only about 5% of babies are born on their exact due date, knowing this estimated date helps you and your healthcare provider track fetal development, schedule important prenatal tests, and prepare for your baby's arrival.
Our pregnancy calculator uses Naegele's Rule, the standard method used by healthcare providers worldwide. This formula adds 280 days (40 weeks) to the first day of your last menstrual period (LMP). For more accuracy, we also adjust for cycle length variations. If you know your conception date (common with IVF or fertility tracking), you can use that for even more precise calculations.
Pregnancy is divided into three trimesters, each approximately 13 weeks long. The first trimester (weeks 1-13) is crucial for fetal development. The second trimester (weeks 14-27) often brings relief from early pregnancy symptoms. The third trimester (weeks 28-40) focuses on fetal growth and preparing for birth. Key milestones include viability at 24 weeks and full-term at 37 weeks.
Remember that every pregnancy is unique. Your actual delivery date may vary by up to two weeks before or after your due date, and this is completely normal. Regular prenatal care with your healthcare provider ensures the healthiest outcome for you and your baby.
Due date calculators provide estimates based on standard 40-week gestation. Only 5% of babies arrive on their exact due date. Most deliver within 2 weeks before or after. Ultrasound dating in the first trimester is more accurate.
Last menstrual period (LMP) is standard unless you know your exact conception date from IVF or fertility tracking. Healthcare providers typically use LMP for consistency, adjusting with ultrasound measurements.
If your cycles vary significantly, due date calculations based on LMP may be less accurate. Discuss with your healthcare provider—they may recommend early ultrasound dating for more precision.