Pregnancy

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.

What does my due date tell me?

The date you receive is an estimate of when you will likely have your baby based on the normal length of a full-term pregnancy. Although only about 3% to 5% of women actually deliver on their expected due date, most women deliver within 14 days of their due date. 1

What's next?

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.

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.

References

Citations

1. Rouse DJ, St John E (2003). Normal labor, delivery, newborn care, and puerperium. In JR Scott et al., eds., Danforth's Obstetrics and Gynecology, 9th ed., pp. 35–56. Philadelphia: Lippincott Williams and Wilkins.