Due Date Calculator Pregnancy Calculator and Calendar

Our Due Date Calculator and Pregnancy calculator will calculate your due date based on your last period and cycle length. Calculating your due date and knowing important pregnancy milestones is a very important part of your prenatal care. Your due date is calculated first by calculating your date of ovulation and fertilization (14 days prior to your next estimated peiod), and then by adding 266 days to that date.

Source: Katz VL (2003). Prenatal care. In JR Scott et al., eds., Danforth's Obstetrics and Gynecology, 9th ed., p. 5. Philadelphia: Lippincott Williams and Wilkins