Gestation Age Calculator
Compute gestational age (weeks + days) from last menstrual period. Not medical advice.
Result
Gestation
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How to use this calculator
- Enter the LMP date.
- Set "as of" to today (default) or any reference date.
- Read weeks + days plus trimester.
About this calculator
Gestational age is conventionally measured from the first day of the last menstrual period (LMP), not from conception (which happens ~2 weeks later). A "term" pregnancy is 38-42 weeks gestational age. This calculator is a formula tool only — pregnancy decisions should be made with a qualified medical professional.
Frequently asked
LMP is ~2 weeks before conception. Gestational age (LMP-based) is what hospitals and OBs use; embryonic age (conception-based) is 2 weeks less.
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