Find your due date, how far along you are, and key pregnancy milestones.
Add 280 days (40 weeks) to the first day of your last menstrual period. This is Naegele's rule, the standard method used by healthcare providers. If your cycle is longer than 28 days, add the extra days to adjust the due date accordingly.
This calculator provides estimates only. Consult your healthcare provider for medical guidance and accurate dating.
The standard method (Naegele's rule) adds 280 days (40 weeks) to the first day of your last menstrual period. This assumes a 28-day cycle. If your cycle is longer than 28 days, you likely ovulate later, which shifts the due date later by the same number of days.
First trimester runs from week 1 to 12. Second trimester from week 13 to 26. Third trimester from week 27 to 40. Key screening tests are typically offered at specific weeks during each trimester.
Full term is defined as 39 weeks 0 days to 40 weeks 6 days. Babies born at 37-38 weeks are early term and may need additional support. Most healthcare providers prefer to wait until at least 39 weeks unless medically necessary.