Pregnancy Due Date Calculator: When Will Your Baby Arrive?
A pregnancy due date calculator estimates the expected date of delivery based on the first day of your last menstrual period (LMP) and your average cycle length. While only about 5% of babies are born on their exact due date, knowing your estimated due date is crucial for prenatal care planning, scheduling important tests and screenings, and preparing for the arrival of your baby.
How the Due Date is Calculated
The standard method, known as Naegele rule, estimates the due date by adding 280 days (40 weeks) to the first day of the last menstrual period. This assumes a 28-day cycle with ovulation occurring on day 14. For women with longer or shorter cycles, the calculation is adjusted accordingly. Our calculator accounts for cycle length variations to provide a more personalized estimate.
Pregnancy Trimesters
Pregnancy is divided into three trimesters: First trimester (weeks 1-12), when major organs begin forming; Second trimester (weeks 13-26), often called the honeymoon period due to reduced morning sickness and increased energy; and Third trimester (weeks 27-40), when the baby grows rapidly and prepares for delivery. Each trimester has specific milestones, medical tests, and developmental checkpoints.
Important Prenatal Care Milestones
Key prenatal appointments include the first ultrasound (typically weeks 8-12), genetic screening (weeks 10-13), anatomy scan (weeks 18-22), glucose tolerance test (weeks 24-28), and Group B Streptococcus test (weeks 35-37). Knowing your due date helps schedule these critical screenings at the optimal time. Remember, a full-term pregnancy ranges from 37 to 42 weeks, and your healthcare provider may adjust your due date based on ultrasound measurements.