Pregnancy Weeks & Due Date Calculator

Your due date is only an estimate as it based on a 28-day menstrual cycle. Your obstetrical provider may correct your due date by taking into consideration the first day of your last menstrual period (LMP) and an ultrasound (sonogram) exam.

Your conception date is approximately two weeks after the first day of your (LMP).

Normal pregnancy last about 280 days (40 weeks), counting from the first day of your LMP. The pregnancy is divided into 3 trimesters:

• First trimester: 0-12 weeks
• Second trimester: 13-27 weeks
• Third trimester: 28-40 weeks

Only 1 in 20 women delivers on their due date. Most women go into labor within 2 weeks before or after their due date.

Using due date:

You can calculate your weeks of pregnancy using the due date determined by your obstetrical provider.
Your due date

Using last menstrual period (LMP):

You can also calculate weeks of pregnancy and due date, or planning pregnancy, using your last menstrual period (LMP).
Your last menstrual period