Calculate your current pregnancy week, trimester, due date, and track your pregnancy progress
This is an estimate for informational purposes only and does not replace professional medical advice. Consult your healthcare provider for accurate pregnancy dating.
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Know exactly where you are in your pregnancy journey. This calculator determines your current pregnancy week, shows which trimester you're in, calculates your due date, and tracks your progress toward delivery day.
Pregnancy is measured from the first day of your last menstrual period (LMP), even though conception occurs about 2 weeks later. A full-term pregnancy is 40 weeks. The first trimester (weeks 1-12) involves rapid cell division. The second trimester (weeks 13-26) brings major organ development. The third trimester (weeks 27-40) focuses on growth and preparation for birth. This 40-week timeline follows Naegele's Rule — the standard obstetric method of dating a pregnancy 280 days from the first day of the LMP — which is why your "weeks pregnant" count from a date about two weeks before conception.
Pregnancy Week Calculation
Know when to schedule glucose tests, anatomy scans, and other milestone appointments.
Each week brings new developments—learn what's happening with your baby.
Use trimester milestones to plan nursery setup, baby shopping, and birth preparation.
Know what developmental stage your baby is at
Prepare for upcoming prenatal appointments
Understand symptoms common to your week
Track progress toward your due date
Plan for each trimester milestone
Most women know their LMP date but not conception date. Since ovulation typically occurs 14 days after LMP in a 28-day cycle, this method provides a consistent starting point for dating pregnancy.
Adjust using the cycle length field. Longer cycles mean ovulation occurs later, so we add those extra days to calculations. For a 35-day cycle, add 7 days to standard calculations.
First trimester: weeks 1-12. Second trimester: weeks 13-26. Third trimester: weeks 27-40. Each has distinct developmental milestones and common symptoms.
Only about 5% of babies arrive on their due date. It's an estimate—full term is 37-42 weeks. Your healthcare provider may adjust based on ultrasound measurements.