👶 EDD Calculator (Estimated Date of Delivery)
Estimate your due date (EDD) and current gestational age using Naegele’s rule, adjusted for your average cycle length.
How due dates are estimated
The most common method for estimating a due date is Naegele’s rule: adding 280 days (40 weeks) to the first day of the last menstrual period (LMP). This assumes a 28-day cycle with ovulation on day 14; the estimate can be adjusted for cycles that run longer or shorter than average.
How this calculator works
Enter how many days have passed since your last period started and your average cycle length. The calculator adjusts the standard 280-day estimate by the difference between your cycle length and 28 days, then shows your current gestational age, trimester, and how many days or weeks remain until your estimated due date.
This tool provides a general educational estimate only, not a medical diagnosis. Only about 5% of babies are born exactly on their due date; an ultrasound dating scan from your healthcare provider is more accurate, especially for irregular cycles.