What is this?
A due date calculator estimates when your baby will arrive using either the last menstrual period (LMP) or conception date. It uses Naegele's Rule: add 280 days (40 weeks) to the first day of your last period. Pregnancy is counted from your last period, not conception, so you're "2 weeks pregnant" at fertilization.How to use
Choose LMP method (most accurate for regular 28-day cycles) or conception date method. Enter the reference date and optionally adjust cycle length if yours differs from 28 days. The calculator shows your due date, current week, trimester, and upcoming milestones.Tips
- Only 5% of babies arrive on their exact due date - most come within 10 days before or after
- First-time mothers average 40 weeks + 5 days, subsequent pregnancies average 40 weeks + 3 days
- Full term is 39-40 weeks (optimal), early term is 37-38 weeks, post-term is 42+ weeks
- First trimester ultrasounds (8-12 weeks) are most accurate (±3-5 days) - accept doctor's adjusted date
- If cycles are irregular or longer than 28 days, adjust the cycle length for better accuracy
- Major milestones: End of 1st trimester (12 weeks), viability (24 weeks), full term (37 weeks)
- Key appointments: First ultrasound (8-12 weeks), anatomy scan (18-22 weeks), glucose test (24-28 weeks)
- Contact your healthcare provider if past 41 weeks without labor or if you have any concerns
- 1st trimester: Morning sickness, fatigue, major organ development
- 2nd trimester: "Honeymoon phase", feel baby movements (16-20 weeks), anatomy scan
- 3rd trimester: Rapid growth, Braxton Hicks contractions, baby drops into pelvis (36+ weeks)
