These calculators were compiled with care and using published formulae (see references)

The results should be used as examples of gestational age determination and fetal size and growth calculation and only for the gestational age ranges indicated in the respective publications. Before using any calculator for clinical decisions, the local population should be verified against the respective normal ranges.


ISUOG does not assume responsibility for the results obtained with these calculators and does not encourage to use this calculator for clinical decisions. By using these calculators you agree with these terms.


Formulae and data used for construction of the ISUOG Biometry Calculators

Boris Tutschek for, release date April 2018

Purpose Publication Range (postmenstrual weeks)
Dating by CRL Papageorghiou et al. UOG 2014 9-13 weeks
Dating by BPD Selbing et al. Acta Obstet Gynecol
Scand 1985
11-24 weeks
BPD, HC, AC, FL Papageorghiou et al. Lancet 2014 14-42 weeks
EFW calculation Hadlock et al. AJOG 1985  
EFW centile calculation derived from Yudkin et al. Early
Hum Dev 1987
24-42 weeks
Thoracic circumference Laudy et al. UOG 2000 20-40 weeks
Tibia, fibula, humerus, ulna, radius Chitty et al. BJOG 1994 12-42 weeks