Calculate your due date, current week, and key milestones.
What date do you know?
From LMP (most common): Naegele's Rule — add 280 days (40 weeks) to the first day of your last menstrual period. This assumes a 28-day cycle and ovulation on day 14.
From conception: Add 266 days (38 weeks) to the estimated conception date.
Trimesters: First = Weeks 1–13, Second = Weeks 14–26, Third = Weeks 27–40.
Viability: Week 24 is generally considered the threshold of viability — from this point, with intensive care, premature survival becomes possible.
⚠️ Due dates are estimates. Only about 4% of babies are born exactly on their due date. Always consult your midwife or OB-GYN for medical guidance and dating ultrasounds.