Pregnancy Due Date Calculator
Calculate estimated due date, current gestational age, and pregnancy milestone timeline
| Milestone Event | Estimated Date | Gestational Stage |
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How to Use This Pregnancy Due Date Calculator
- Choose your calculation anchor in Calculation Method (LMP, Conception Date, or IVF Transfer).
- Enter the exact date into Select Date.
- Adjust your Average Cycle Length (default is 28 days) if using the LMP method.
- Click “Calculate Due Date & Milestones” to get your gestational breakdown and developmental timeline.
The Due Date Formula (Naegele’s Rule)
Standard pregnancy calculations assume a 280-day (40-week) total gestational period starting from the first day of the last menstrual period:
Frequently Asked Questions (FAQ)
How accurate is the estimated due date (EDD)?
Only about 4% to 5% of babies are born precisely on their estimated due date. Most births occur within a window of two weeks before or two weeks after (38 to 42 weeks).
What is the difference between gestational age and fetal age?
Gestational age measures pregnancy from the first day of your last period (LMP). Fetal age measures actual growth starting from conception (typically 2 weeks after LMP).
Why might an ultrasound change my due date?
If an early first-trimester ultrasound (crown-rump length scan) differs from your LMP due date by more than 5–7 days, healthcare providers typically adjust the official due date to match the ultrasound measurements.