Health
Pregnancy Due Date Calculator
Estimate your due date from the first day of your last menstrual period.
📅 Last updated: July 2, 2026
· Reviewed by the MyCalcKit Editorial Team
How this calculator works
Uses Naegele's rule: adds 280 days (40 weeks) to the first day of your last menstrual period, assuming a typical 28-day cycle. An ultrasound dating scan is more accurate, especially for irregular cycles.
This is an estimate for general reference only — fewer than 5% of babies arrive on their exact due date. Always confirm dating with your midwife or doctor.