Pregnancy Due Date Calculator

How due date calculation works

The standard method (Naegele's rule) adds 280 days (40 weeks) to the first day of the last menstrual period (LMP), assuming a 28-day cycle. For irregular cycles, the ovulation date is estimated by subtracting 14 days from the cycle end. Conception date calculations subtract 14 days to estimate LMP. IVF day-3 transfer adds 2 days to align with a day-5 (blastocyst) timeline then adds the standard 266 days. All dates are estimates — only an ultrasound and your OB can give a confirmed due date.