Calculate your due date and track weekly milestones using Naegele's rule
Pregnancy Due Date Calculator is a free health and wellness calculator that helps you calculate your due date and track weekly milestones using naegele's rule. Understanding your body's metrics is the first step toward making informed health decisions. This tool uses clinically recognized formulas to provide instant, accurate estimates — though always consult a healthcare professional for medical advice.
This calculator uses Naegele's rule: add 280 days (40 weeks) to the first day of your last menstrual period (LMP). This assumes a 28-day cycle with ovulation on day 14. If your cycles are longer or shorter, your actual due date may differ. An early ultrasound is the most accurate way to confirm gestational age and due date.
Pregnancy is divided into three trimesters. The first trimester (weeks 1–12) covers early organ development and carries the highest risk of miscarriage. The second trimester (weeks 13–27) is often called the "golden period" — morning sickness eases and movement is felt. The third trimester (weeks 28–40) involves rapid fetal growth and preparation for birth.
A full-term pregnancy is between 39 weeks 0 days and 40 weeks 6 days. Babies born at 37–38 weeks are "early term," while those at 41+ weeks are "late term." Full-term babies generally have the best outcomes for lung maturity, brain development, and feeding. Elective inductions before 39 weeks are typically discouraged without medical indication.