Estimate due date
Naegele-style estimate
The LMP method assumes a typical 280-day pregnancy counted from the first day of the last period, with an adjustment for cycle length when needed.
Conception estimate
If you know the conception date, the calculator adds 266 days to estimate the due date and then maps the trimester timeline from there.
How it works
For the LMP method, this calculator adds 280 days to the first day of your last menstrual period and adjusts for cycle length if your average cycle is shorter or longer than 28 days. For conception date, it adds 266 days.
Gestational age is shown relative to today based on the selected method. Trimester milestones are approximate planning markers, not exact clinical checkpoints.
This tool is not medical advice. Ultrasound dating and guidance from a clinician are the best sources for a medical due date estimate.