Pregnancy Due Date Calculator
Due Date
Conception Date
Current Status
Due Date Range
Pregnancy Progress
How We Calculate
We use Naegele’s rule, which assumes a 28-day cycle and adds 280 days (40 weeks) to the first day of your last menstrual period. We then adjust for your specific cycle length. Remember, only about 5% of babies are born on their exact due date, and it’s normal for birth to occur up to two weeks before or after this date.
Understanding Pregnancy Calculation
Pregnancy calculation is a fascinating blend of medical science and mathematical precision. Our calculator uses Naegele’s rule, a time-tested method that has been helping healthcare providers and expectant parents since the early 19th century.
Accurate Due Date
Using sophisticated calculations based on your last menstrual period and cycle length to provide a precise estimated due date.
Visual Progress
Track your pregnancy’s progression with our interactive visualization, showing fetal development week by week.
Smart Adjustments
Accounts for variations in menstrual cycle length, providing personalized calculations for more accurate results.
How Pregnancy Dating Works
Understanding Gestational Age
Pregnancy is typically calculated from the first day of your last menstrual period (LMP), not from the day of conception. This method is used because while conception date can be uncertain, most women can recall their last period.
The Science Behind the Calculation
Our calculator uses Naegele’s rule, which adds 280 days (40 weeks) to the start of the last menstrual period. This method has been refined with modern research to account for variations in cycle length.
Understanding the Due Date Range
While we provide a specific due date, it’s important to understand that only about 5% of babies are born exactly on their due date. Most births occur within two weeks before or after this date, which is why we provide a date range.
Key Pregnancy Milestones
First Trimester (Weeks 1-13)
Major organ systems develop, morning sickness may occur, and rapid cell division takes place.
Second Trimester (Weeks 14-26)
Baby’s movements become noticeable, gender can often be determined, and many women feel more energetic.
Third Trimester (Weeks 27-40)
Rapid growth continues, baby gets into birth position, and final preparations for birth occur.
Important Notes
Accuracy Considerations
- Due dates are estimates based on averages
- Individual pregnancies can vary significantly
- Regular prenatal care is essential for monitoring progress
- Cycle length variations are accounted for in calculations
When to See Your Doctor
- As soon as you suspect pregnancy
- For regular prenatal checkups
- If you have concerns about your due date
- To confirm calculator results professionally