Pregnancy Weeks Calculator.

Identify pregnancy gestational timeline, key trimester benchmarks, and baby size metrics.

Input Parameters

First Day of Last Period

Manual Keyboard Input / Calendar

Dropdown Selectors

Documentation

Detailed manual explaining every function, input parameter, and operational example for the Pregnancy Weeks Calculator.

Function

First day of last menstrual period (LMP).

Example Operation LMP = 2026-01-01

Function

Computes pregnancy week, day, trimester, and due date.

Example Operation LMP 2026-01-01 on 2026-08-09 -> 31 weeks 3 days (3rd Trimester, Due Oct 8, 2026)

How are pregnancy weeks calculated?

Pregnancy weeks are counted from the first day of your last menstrual period (LMP). A full-term pregnancy is 40 weeks (280 days) from the LMP date.

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