Pregnancy Due Date Calculator: Estimate EDD, Gestational Age & Milestones

Enter the first day of your last period, conception, or embryo-transfer date and your usual cycle length; the calculator adds 280 days (plus any cycle adjustment) to estimate birth, a method that brackets 90 % of deliveries within ±14 days (ACOG, 2017). It also shows gestational age, trimester and key fetal milestones.