Pregnancy Due Date Calculator
This tool estimates your due date (about 40 weeks from the first day of your last period) and your current gestational age in weeks. Enter the first day of your last menstrual period. The result is an estimate based on Naegele’s rule; an OB-GYN confirms the exact date by ultrasound.
Medical disclaimer: This tool is for general informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
Frequently asked questions
How is the due date calculated?
By adding 280 days (40 weeks) to the first day of your last menstrual period (Naegele’s rule), assuming a regular 28-day cycle.
Is the calculated date accurate?
It is a good estimate, but only about 5% of births occur on the exact calculated date. A first-trimester ultrasound gives a more precise gestational age.
When should I see an OB-GYN?
A first visit is advised once pregnancy is confirmed (missed period + positive test), then regular follow-ups. Seek care immediately for bleeding or severe pain.