🍼 Due Date Calculator
Estimate your baby's due date and see your complete pregnancy timeline.
How Due Date Calculations Work
The most common method is Naegele's Rule: add 280 days (40 weeks) to the first day of your last menstrual period (LMP). This assumes a 28-day cycle and ovulation on day 14. If your cycle is longer or shorter, your actual due date may shift slightly.
For IVF pregnancies, the calculation starts from egg retrieval: a Day 3 transfer adds 263 days, and a Day 5 (blastocyst) transfer adds 261 days. Your doctor may adjust all estimates after your first ultrasound.
Important: Only ~5% of babies arrive on their exact due date
A due date is an estimate, not a deadline. Most healthy births happen within the two-week window before and after the estimated date. The medical term for this full-term range is 37–42 weeks of gestation.
Your Three Trimesters at a Glance
| Trimester | Weeks | Key Milestones |
|---|---|---|
| First | 1–13 | Heart begins beating (week 6), major organs form, first prenatal visit |
| Second | 14–26 | Baby moves (week 18–22), anatomy scan ultrasound, gender can be detected |
| Third | 27–40 | Rapid weight gain, lungs mature, baby repositions head-down, birth preparation |
🏥 Always follow your OB/GYN's guidance. This calculator provides estimates — your doctor's ultrasound measurements are the gold standard for dating your pregnancy.