Understanding Crown-Rump Length (CRL) & Dating:
The Crown-Rump Length (CRL) is the measurement of the length of the embryo or fetus from the top of its head (crown) to the bottom of its buttocks (rump). It’s one of the most accurate ways to estimate gestational age in early pregnancy.
This calculator uses a commonly accepted formula (Hadlock et al.) to estimate gestational age based on your CRL measurement. This method is most accurate between approximately 6 and 14 weeks of gestation, when the CRL is typically between 2 mm and 84 mm.
Estimated Gestational Age: Your current estimated pregnancy duration based on the CRL.
Estimated Due Date (EDD): The approximate date your baby is expected to be born. This is calculated by adding 280 days (40 weeks) to an estimated Last Menstrual Period (LMP) date, which is derived from your current gestational age.
Estimated Conception Date: The approximate date when fertilization likely occurred. This is typically about 266 days (38 weeks) before your Estimated Due Date.
While CRL measurements provide very accurate dating in early pregnancy, these calculations are estimates. Your healthcare provider will provide the most precise dating based on a comprehensive assessment, including ultrasound findings and your medical history.
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