This interactive tool calculates your pregnancy due date, an estimate of when you are likely to deliver your baby.
To find your due date, the calculator takes the first day of your last menstrual period (LMP) and adds 40 weeks. If you are planning a pregnancy, you can use this calculator to plan the birth for a certain month or season.
Katz VL (2008). Prenatal care. In RS Gibbs et al., eds., Danforth's Obstetrics and Gynecology, 10th ed., p. 4. Philadelphia: Lippincott Williams and Wilkins.
What does your due date tell you?
Your due date is an estimate of when you will likely have your baby, based on the normal length of a full-term pregnancy. Most women deliver within 14 days of their due date.
Your health professional will also measure the size of your uterus and use ultrasound testing to determine your due date. For more information on planning a healthy pregnancy, see the topic Pregnancy.
Other Works Consulted
Bernstein HB, Van Buren G (2013). Normal pregnancy and prenatal care. In AH DeCherney et al., eds., Current Diagnosis and Treatment Obstetrics and Gynecology, 11th ed., pp. 141–153. New York: McGraw-Hill.
Katz VL (2008). Prenatal care. In RS Gibbs et al., eds., Danforth's Obstetrics and Gynecology, 10th ed., pp. 1–21. Philadelphia: Lippincott Williams and Wilkins.
ByHealthwise Staff Primary Medical ReviewerSarah A. Marshall, MD - Family Medicine Thomas M. Bailey, MD, CCFP - Family Medicine Adam Husney, MD - Family Medicine Kathleen Romito, MD - Family Medicine Kirtly Jones, MD - Obstetrics and Gynecology, Reproductive Endocrinology