🤰 Pregnancy Due Date Calculator

Estimate a due date with Naegele’s rule from the last menstrual period, or work backwards from a known due date. Shows gestational week, trimester and days remaining. This is an educational estimate, not medical advice.

I know

That date

Typical cycle length (days)

Estimated due date

Trimester
Days remaining
Conception (est.)
End of first tri
End of second tri

Naegele’s rule adds 280 days to LMP, then shifts by (cycle − 28) days. Only a clinician can confirm dates with an ultrasound.