Calculate your pregnancy due date, current week and trimester.
A pregnancy calculator estimates your due date, current week of pregnancy, and key milestones based on your last menstrual period (LMP) or conception date. Our free online pregnancy due date calculator also shows your trimester progress, important prenatal checkup timelines, and weekly fetal development milestones.
The standard method uses Naegele's Rule: add 280 days (40 weeks) to the first day of your last menstrual period. For example, if your LMP was January 1, your estimated due date is October 8. This assumes a regular 28-day cycle with ovulation on day 14. Our due date calculator applies this formula instantly.
Week 8-10: First prenatal visit, confirm pregnancy, blood tests. Week 11-13: NT scan (nuchal translucency) for chromosomal screening. Week 18-20: Anomaly scan to check fetal anatomy and gender (optional). Week 24-28: Glucose tolerance test for gestational diabetes. Week 36+: Weekly checkups, Group B Strep test, birth plan discussion.
Regular fetal movement after week 18-20, steady weight gain (1-2 kg per trimester in first half, then 0.5 kg per week), normal blood pressure, clear urine, and positive prenatal test results indicate a healthy pregnancy. Always consult your gynecologist or obstetrician for personalized guidance. This calculator is an informational tool — not a substitute for professional medical care.
Due date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period (LMP). This is Naegele's rule.
Only about 5% of babies are born on their exact due date. Most births happen within 2 weeks before or after the estimated due date.
Pregnancy is divided into three trimesters: First (weeks 1-12), Second (weeks 13-27), and Third (weeks 28-40).
If your cycle is irregular, the due date based on LMP may be less accurate. An ultrasound in early pregnancy provides a more precise due date.
