HEALTH REFERENCES WITH CLEAR LIMITS
Pregnancy Week Calculator
Estimate completed pregnancy weeks between the first day of the last menstrual period and a selected date.
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How it works
Completed pregnancy weeks are counted from the first day of the last menstrual period to the selected date.
Assumptions
This is a calendar estimate and may differ from clinical dating.
Use case
pregnancy week calculator: a clear planning check
Estimate completed pregnancy weeks between the first day of the last menstrual period and a selected date. The stated formula, assumptions, and result limits remain visible so the calculation can be checked in context.
Use a clear pregnancy week calculator scenario with values you can verify before relying on the result.
Source and update
Last reviewed: 2026-08-10
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