Health tool
Pregnancy Due Date Calculator
Estimate your due date and current week, based on your last period or a known conception date.
—Estimated due date
—Current week
—Trimester
How this is estimated
From the last period, this uses Naegele's rule: 280 days (40 weeks) after that date, based on an average 28-day cycle. From a conception date, it adds 266 days (38 weeks) instead. Only about 5% of babies arrive exactly on the estimated date — it's a useful planning marker, not a precise prediction.