Pregnancy Due Date Calculator

This calculator estimates your due date, current weeks pregnant, trimester, and likely conception date based on the first day of your last menstrual period (LMP).

It uses Naegele's Rule, which adds 280 days (40 weeks) to your LMP date, assuming a standard 28-day cycle. Conception is estimated as 14 days after LMP, the typical timing of ovulation, and the current trimester is derived from how many weeks have passed since then.

Example: With an LMP of October 1, the estimated due date would be July 7 the following year — and by week 20, you'd be in your second trimester.