Side-by-side comparison helps you choose the right calculator for a specific clinical question.
Obstetrics
Calculate estimated fetal weight (EFW) using the Hadlock formula from ultrasound biometry: BPD, HC, AC, and FL. Instantly classify SGA, AGA, or LGA by gestational age.
Formula
Hadlock: log₁₀(EFW) = 1.3596 + 0.0064(HC) + 0.0424(AC) + 0.174(FL) + 0.00061(BPD)(AC) − 0.00386(AC)(FL). All measurements in cm.
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Obstetrics
Calculate gestational age in weeks and days from your last menstrual period (LMP). Instantly see trimester, estimated due date, and days remaining. Free and accurate.
Formula
Gestational Age = days since LMP. EDD = LMP + 280 days (Naegele's rule).
Inputs