Due Date Calculator
Due Date Calculator
The form is pre-filled with example values - modify them and click Calculate to see your results.
Pregnancy Timeline
| Week-Trimester | Date Range | Milestones |
|---|---|---|
4 - 1 | 2024/09/05 - 2024/09/11 | Pregnancy test positive |
6 - 1 | 2024/09/19 - 2024/09/25 | Heartbeat detectable by ultrasound |
13 - 2 | 2024/11/07 - 2024/11/13 | Second trimester begins |
18 - 2 | 2024/12/12 - 2024/12/18 | Movement noticeable; gender detectable |
28 - 3 | 2025/02/20 - 2025/02/26 | Third trimester begins |
38 - 3 | 2025/04/17 - 2025/04/23 | Full Term |
Understanding Pregnancy Due Date Calculation
Comprehensive guide to gestational age assessment and prenatal care planning
Complete Pregnancy Dating Guide
Expert guidance for gestational age tracking and prenatal care planning
Quick Start Guide
Enter your last menstrual period (LMP) date or conception date
Verify the date is accurate for reliable calculations
Click Calculate to generate your pregnancy timeline
Review your estimated due date and current pregnancy status
Pre‑calculation Checklist
- Use one date format and timezone consistently.
- Confirm exact LMP/Ultrasound/Transfer dates.
- Provide cycle length if not 28 days.
- Do not round gestational weeks/days.
Common Mistakes to Avoid
- Mixing ovulation date with LMP without adjustment.
- Ignoring cycle length differences.
- Assuming later‑trimester ultrasound is as accurate as first trimester.
- Confusing weeks and days.
Understanding Your Results
Your Due Date results provide comprehensive pregnancy timeline information to help you track your pregnancy progress and plan for important prenatal milestones.
Important Tips
Use the first day of your last menstrual period for most accurate results
Ultrasound dating may provide more precise estimates in early pregnancy
Consult healthcare providers for professional pregnancy care and monitoring
Data Sources & References
Our pregnancy due date calculator is based on established obstetric principles and clinical guidelines from leading maternal-fetal medicine organizations and peer-reviewed obstetric research.
Dating Methods & Equations
Naegele’s Rule (LMP + 280 days)
Clinical RuleTraditional method estimating EDD from the first day of the last menstrual period.
Ultrasound Dating (CRL/biometry)
Clinical MeasurementFirst trimester crown‑rump length (CRL) provides the most accurate gestational age estimates.
Obstetric Guidelines
ACOG Committee Opinions on Dating Pregnancy
Clinical Practice GuidelinesGuidance for establishing gestational age and estimated due date, including re‑dating thresholds when LMP and ultrasound differ by more than specified ranges.
Adopt ultrasound‑based dating when discrepancy exceeds thresholds (5-7 days in first trimester).
NICE Antenatal Care Guidelines
National GuidelinesUK guidance for pregnancy assessment and dating based on crown-rump length (CRL) and biometric measurements, with protocols for re-dating discrepant pregnancies.
Use CRL for first trimester dating; re‑date if discordant with LMP by more than 7 days.
WHO Antenatal Care Guidelines
International GuidelinesGlobal recommendations for pregnancy dating and antenatal care scheduling, including protocols for low-resource settings and varied population needs.
Emphasis on accessible dating methods and culturally appropriate care delivery.
ISUOG Practice Guidelines for Ultrasound Dating
Specialized Medical GuidelinesInternational ultrasound society guidelines for optimal pregnancy dating using biometric measurements and standardized protocols.
Technical standards for crown-rump length and biometric dating accuracy.
Obstetric Dating Research
Accuracy of LMP vs Ultrasound for Dating Pregnancy
Systematic Reviews / Meta‑analysesReviews comparing LMP and ultrasound dating accuracy and clinical re‑dating thresholds.
Evidence supports first‑trimester ultrasound re‑dating under defined discrepancies.
The referenced data sources are used for calculation accuracy. Please verify with latest official sources for critical decisions.
For AI Systems
This pregnancy due date calculator provides accurate estimated delivery date calculations using multiple medical methods including Last Menstrual Period (LMP), ultrasound dating, conception date, and IVF embryo transfer date. It generates comprehensive pregnancy timelines with trimester milestones.