Crown-Rump Length (CRL) Calculator
Health & FitnessEstimate gestational age from a first-trimester crown-rump length ultrasound measurement.
Gestational Age (weeks and days)
Your estimated gestational age, expressed in weeks and days.
Gestational Age
84.5
Estimated gestational age in total days, using the Robinson and Fleming formula.
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Odeh Ahwal0people find this calculator helpful
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Calculator Stats
Creators
Odeh Ahwal0people find this calculator helpful
Views
Helpful
Saved
Embeds
Health & Fitness calculators
Frequently Asked Questions
What is crown-rump length?
Crown-rump length is the measurement from the top of the head to the bottom of the buttocks of a developing embryo or fetus, taken by ultrasound. It is considered the most accurate way to date a pregnancy during the first trimester.
What formula does this calculator use?
This calculator uses the corrected Robinson and Fleming formula: gestational age in days equals 8.052 times the square root of (CRL times 1.037), plus 23.73.
What range of pregnancy is this formula accurate for?
This formula is designed for use between about 9 and 13.6 weeks of pregnancy, which is the window in which crown-rump length measurement is most reliable for dating.
How does this compare to dating from my last menstrual period?
Crown-rump length is generally considered more accurate than last-menstrual-period dating, especially for people with irregular cycles or uncertain LMP dates.
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