Pregnancy Due Date Calculator

What this calculator does

It estimates an expected due date based on the first day of your last menstrual period (LMP) assuming a 28‑day cycle.

How the due date is calculated

Naegelé’s rule: add 280 days (40 weeks) to the LMP date. Actual due dates vary and clinical guidance is essential.

Who should use this

• Expecting parents planning timelines
• Educational purposes; not a medical diagnosis

Examples

• LMP: 2025‑01‑10 → Due date ≈ 2025‑10‑17
• LMP: 2025‑03‑01 → Due date ≈ 2025‑12‑06