Pregnancy Due Date Calculator
Estimate your due date from your last menstrual period (LMP), a known conception date, or an already-known due date.
This tool is for general informational purposes only and is not medical advice. It does not diagnose, treat, or replace consultation with a qualified healthcare provider.
What this tool does
Estimate your due date from your last menstrual period (LMP), a known conception date, or an already-known due date.
Method used
Naegele's rule: due date = last menstrual period + 280 days (40 weeks), or conception date + 266 days (38 weeks). Trimester milestones are approximate week-based markers, not clinical cutoffs.
Frequently asked questions
How accurate is this estimate?
Naegele's rule assumes a regular 28-day cycle; only about 5% of babies arrive exactly on the estimated date, and a clinical ultrasound dating is more accurate than a calendar-based estimate.
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