Due Date Calculator

Find out when your little one is likely to arrive.

How Is a Due Date Calculated?

Due dates use Naegele's rule: add 280 days (40 weeks) to the first day of your last period. Only about 5% of babies arrive on their exact due date — most come within two weeks before or after.

Factors That Affect Your Due Date

  • Cycle length — longer cycles may mean a later due date
  • First vs. subsequent pregnancies
  • Maternal age and health conditions
  • Multiple births (twins typically arrive earlier)