What is an EDD calculator?

An EDD calculator helps you estimate your date of delivery ("due date") based on the timing of your last menstrual period. Gestational age estimates how far along you are in your pregnancy. Your health care provider uses the gestational age in weeks (rather than months) to plan your care during pregnancy. Most pregnancies last about 40 weeks from the first day of the last menstrual period. To calculate your estimated due date and gestational age, enter the current date and the date your last menstrual period started.