Health
Pregnancy Due Date
Estimate a baby’s due date from the last menstrual period (LMP) and track trimester milestones with a cycle-length adjustment.
Naegle’s rule with cycle-length adjustment and milestone checkpoints.
Naegle’s rule with cycle offset
Due date = LMP + 280 days + (cycle length − 28)
The tool maps Naegele’s rule to your specific cycle. It also projects second trimester (13 weeks) and viability (24 weeks) checkpoints from the same starting date.
How to use
- Select the LMP date on the calendar input.
- Enter your average cycle length (default 28 days).
- Review the due date, weeks along as of today, trimester stage, and milestone dates.
Example
Input: LMP = 15 Jan 2024, Cycle length = 28 days
Output: Estimated due date = 21 Oct 2024, Second trimester begins = 15 Apr 2024, Viability (24 weeks) = 1 Jul 2024
FAQ & notes
What if my cycles are irregular?
Use your best average. For significantly irregular cycles, confirm timelines with an ultrasound for maximum accuracy.
Does this replace medical advice?
No. The calculator offers an educational estimate and should be validated with your healthcare provider.