Robinson-Fleming CRL Dating
Robinson-Fleming crown-rump-length dating: gestational age (days) = 8.052 x sqrt(1.037 x CRL) + 23.73, CRL in mm; validated for CRL 5-84 mm.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Crown-rump length
- 30 mm
Result: Robinson-Fleming gestational age 9 weeks 6 days (69 days) from CRL 30 mm.
The tool opens with these values already filled in. Replace them with your own.
What the result means
- CRL 5-84 mm
- GA (days) = 8.052 x sqrt(1.037 x CRL) + 23.73; accurate to +/- 3-5 days (NICE/RCOG/ISUOG). A dating estimate, not a diagnosis.
What you enter
- Crown-rump length
How this is calculated
Robinson HP, Fleming JEE. A critical evaluation of sonar crown-rump length measurements. Br J Obstet Gynaecol. 1975;82(9):702-710. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.