Pregnancy Due Date Calculator
Estimate your pregnancy due date based on your last menstrual period.
What This Calculator Does
The Pregnancy Due Date Calculator estimates your due date based on the first day of your last menstrual period (LMP). It also shows your current pregnancy week, trimester, and key trimester milestones.
How the Calculation Works
Enter the first day of your last menstrual period. The calculator applies Naegele's rule — adding 280 days (40 weeks) to the LMP — to estimate the due date. It then determines your current pregnancy week and trimester based on today's date, and displays the end dates of each trimester.
Example Scenario
A expectant mother's last menstrual period began on January 10, 2026. Entering January 10 shows an estimated due date of October 17, 2026. The tool also shows she is currently in her second trimester and displays when each trimester ends.
Common Use Cases
- ✓ Estimating pregnancy due dates for planning
- ✓ Tracking current pregnancy week and trimester
- ✓ Planning maternity leave and work transitions
- ✓ Scheduling prenatal appointments and milestones
How to Use
1.Enter the first day of your last menstrual period.
2.See your estimated due date.
3.View current pregnancy week and trimester milestones.
Benefits
- ✓ Based on standard Naegele's rule
- ✓ Shows current week and trimester
- ✓ Trimester end dates included
Frequently Asked Questions
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Category
Planning Tools
Plan project timelines, school schedules, pregnancy due dates, and life milestones.
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View all →Related Glossary Terms
Due Date
The date by which a payment, delivery, or task must be completed. Due dates are commonly used in invoicing (e.g., Net 30), project management, and pregnancy (estimated delivery date).
Pregnancy Week
One of the 40 weeks of a typical human pregnancy, counted from the first day of the last menstrual period. Pregnancy milestones and trimesters are measured in weeks.
Trimester
A period of approximately three months, used both in academic scheduling (dividing the school year into thirds) and in pregnancy (dividing gestation into three developmental phases).
Estimated Due Date (EDD)
The projected date when a baby is expected to be born, calculated as approximately 40 weeks (280 days) from the first day of the last menstrual period. Also called the estimated date of confinement (EDC).
Gestation Period
The length of time from conception to birth. In humans, the typical gestation period is approximately 40 weeks (280 days) from the last menstrual period.