Due Date Calculator
Estimate your pregnancy due date and view milestone dates.
How Due Dates Are Calculated
Naegele's Rule adds 280 days (40 weeks) to the first day of your last menstrual period. Only about 5% of babies are born exactly on their due date — most arrive within 2 weeks before or after. Ultrasound dating, especially before 12 weeks, is more accurate than menstrual dates alone.
Pregnancy Trimesters: What to Expect
First trimester (weeks 1-12): major organ development occurs, morning sickness is common, and miscarriage risk is highest. Second trimester (weeks 13-27): energy often returns, baby movements begin around 18-20 weeks, and the anatomy scan typically occurs at week 20. Third trimester (weeks 28-40): rapid growth, Braxton Hicks contractions may begin, and preparation for birth.
Factors That Affect Your Due Date
First-time mothers tend to go about 4 days past their due date on average. Multiple pregnancies (twins, triplets) typically arrive earlier. If your cycle is shorter or longer than 28 days, the calculator adjusts accordingly. Always follow your healthcare provider's guidance for the most accurate dating.