Due Date Calculator
Calculate your pregnancy due date using your last menstrual period, conception date, IVF transfer, or ultrasound measurements.
Calculation Method
Average cycle is 28 days. Adjust if yours is different.
Current Trimester
1st Trimester
1-12 weeks
2nd Trimester
13-26 weeks
3rd Trimester
27-40 weeks
Estimated Due Date
Thursday, September 10, 2026
220 days remaining
Estimated Conception
12/18/2025
Gestational Age at Ultrasound
8 weeks, 4 days
Safe Delivery Range
8/20/2026 - 9/24/2026
Most babies are born between 37-42 weeks
Pregnancy Milestones
Week 4: Implantation
1/1/2026
Week 6: Heartbeat
1/15/2026
Week 8: First Prenatal
1/29/2026
Week 10: Fetal Stage
2/12/2026
Week 12: End of 1st Trimester
2/26/2026
Week 16: Gender Reveal
3/26/2026
Week 20: Anatomy Scan
4/23/2026
Week 24: Viability
5/21/2026
How is the Due Date Calculated?
The most common method uses Naegele's Rule: Add 280 days (40 weeks) to the first day of your last menstrual period (LMP). This assumes a 28-day cycle.
Naegele's Rule
This method, developed in the 1800s, adds 280 days to your LMP or 266 days from conception. It assumes ovulation occurs on day 14 of a 28-day cycle.
How Accurate is the Due Date?
Only about 5% of babies are born on their due date. Most babies arrive within 2 weeks before or after. The "due date" is best thought of as an estimate.
Important Notes
- 1This calculator provides estimates only - consult your healthcare provider
- 2First-trimester ultrasounds are most accurate for dating pregnancy
- 3Irregular cycles may affect LMP-based calculations
- 4IVF patients should use their transfer date for highest accuracy
- 5Due dates are adjusted if ultrasound measurements differ significantly