Estimated Due Date
Calculate the estimated date of delivery
Result
Estimated Due Date (EDD)
Current gestational age:
Trimester:
Time remaining:
How the Calculation Works
Naegele's Rule (LMP)
280 days (40 weeks) are added to the date of the last menstrual period. This is the most traditional method and assumes regular 28-day cycles with ovulation on day 14.
Conception Date
266 days (38 weeks) are added to the conception date. As gestational age is counted from the LMP (approximately 14 days before conception), the current GA is calculated from the equivalent LMP.
Ultrasound
From the gestational age identified on the ultrasound, the number of days remaining to complete 40 weeks is calculated. A first-trimester ultrasound is considered the most accurate method for gestational dating (ACOG).
Note: The EDD is an estimate — only around 5% of babies are born on the exact predicted date. Physiological delivery occurs between 37 and 42 weeks of gestation. Regular prenatal care is essential for monitoring the health of both mother and baby.