Due Date Calculator 2026 – Calculate Baby's Expected Birth Date
The due date calculator calculates baby's estimated birth date based on the first day of last menstrual period or conception date. The tool also shows pregnancy weeks and important checkup appointments.
Due date is calculated by adding 280 days (40 weeks) to the last menstrual period. The calculator shows current pregnancy week, trimester, and estimated prenatal appointment dates. Only about 5% of babies are born exactly on their due date — normal delivery occurs between weeks 37–42.
How is due date calculated?
The most common method is Naegele's rule: add 1 year to the first day of last menstrual period, subtract 3 months, and add 7 days. For example, if menstruation started on January 1, 2026, the due date is October 8, 2026. Ultrasound usually refines the estimate during the first prenatal visit.
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Browse all tools →The due date calculator estimates the pregnancy due date based on last menstrual period or conception date. A useful tool for expectant parents to track pregnancy stages.
Enter the start date of last menstrual period or conception date, and the calculator estimates the due date.
- Estimates due date based on last menstrual period (Naegele's rule).
- Shows pregnancy stage and gestational weeks at the current time.
- Provides an indicative timeline for different pregnancy stages.
The due date is an estimate – only about 5% of babies are born exactly on the due date.
- Normal delivery usually occurs between 37-42 gestational weeks.
- Ultrasound examination gives a more accurate estimate than menstrual-based calculation.
- Irregular cycles can affect the accuracy of the calculation.
The calculator is an indicative tool, not a medical device.
- The official due date is determined at prenatal clinics with ultrasound.
- Pregnancy monitoring always belongs to healthcare professionals.
- Your data is not stored – you can use the calculator privately.