How is the estimated due date calculated?

Your estimated due date (EDD) is calculated by adding exactly 280 days (or 40 weeks) to the first day of your last menstrual period (LMP).

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Pregnancy Due Date Calculator

Calculate your estimated baby due date and track your current trimester progress.

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First Day of Last Menstrual Period (LMP)

Understanding Your Estimated Due Date

An Expected Date of Delivery (EDD/EDC) is medically calculated by tracking forward from the first day of your Last Menstrual Period (LMP).

The 280-Day Rule

Biologically, standard human gestation spans 40 weeks. Because pregnancy dating traditionally begins from the LMP rather than the exact date of conception, the math mathematically adds exactly 280 days to generate the projected forecast.

Our tool also calculates your immediate placement within the standard trimesters, allowing you to trace your baby's relative week-by-week development schedule accurately.