Pregnancy Calculator
Calculate your due date and track pregnancy milestones with our accurate pregnancy calculator. Get week-by-week pregnancy timeline and important dates.
Calculator
Enter your information to calculate results
About Pregnancy Calculation
Pregnancy typically lasts about 40 weeks (280 days) from the first day of your last menstrual period (LMP) or 38 weeks (266 days) from conception. These are estimates as every pregnancy is unique.
Key Milestones:
How It Works
How Pregnancy Calculation Works
Our pregnancy calculator uses standard medical methods to estimate your due date and track pregnancy milestones.
LMP Method
- • Uses first day of last menstrual period
- • Adds 280 days (40 weeks) for due date
- • Most commonly used method
- • Assumes 28-day cycle with ovulation on day 14
Conception Date Method
- • Uses known conception date
- • Adds 266 days (38 weeks) for due date
- • More accurate if conception date is known
- • Often used with IVF pregnancies
Pregnancy Trimesters
First Trimester
Weeks 1-13: Organ development
Second Trimester
Weeks 14-26: Growth and movement
Third Trimester
Weeks 27-40: Final development
Examples
Pregnancy Calculation Examples
LMP Method Example
Last Period: January 1, 2024
Due Date: October 8, 2024
Pregnancy Length: 280 days
Total: 40 weeks
Conception Method Example
Conception: January 15, 2024
Due Date: October 8, 2024
Pregnancy Length: 266 days
Total: 38 weeks
Trimester Breakdown
1st Trimester: Weeks 1-13
2nd Trimester: Weeks 14-26
3rd Trimester: Weeks 27-40
Full Term: Week 37+
Important Dates
Viability: Week 24
Full Term: Week 37
Due Date: Week 40
Post-term: Week 42+
Compare
Pregnancy Calculation Methods Comparison
| Method | Accuracy | Common Use | Duration |
|---|---|---|---|
| LMP Method | Good | Most Common | 280 days |
| Conception Date | Very Good | IVF/Known Date | 266 days |
| Ultrasound Dating | Excellent | Medical Standard | Variable |
Important Note
Only about 5% of babies are born on their exact due date. Most babies are born within 2 weeks before or after the estimated due date. Always consult with your healthcare provider for accurate pregnancy monitoring.
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