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Quickly estimate fetal weight using ultrasound data like Biparietal Diameter (BPD), Abdominal Circumference (AC), and Femur Length (FL). Uses the Hadlock formula to provide a reliable reference for pregnancy assessment.
The length of the widest part between the left and right sides of the fetal head
The circumference of the fetal abdomen
The length of the fetal thigh bone
Chinese obstetric guidelines recommended formula: Y = 1.07×BPD³ + 0.3×AC²×FL, applicable to most gestational weeks.
Enter ultrasound data to start calculation
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Calculate the minimum daily calories your body needs at rest based on gender, height, weight, and age. Get a scientific reference for your diet and fitness plans.
Child Height Predictor Calculator
Enter the parents' heights and the child's gender to predict the child's adult height range based on classic genetic formulas.
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At 38 weeks of pregnancy, with a biparietal diameter (BPD) of 9.5 cm, abdominal circumference (AC) of 36.5 cm, and femur length (FL) of 7.6 cm, the estimated fetal weight is about 3,000 grams—this is exactly what fetal weight estimation aims to calculate. Fetal weight estimation involves using ultrasound measurements of the fetus's head, abdomen, and legs, and applying them to medically validated formulas to calculate the approximate current weight of the fetus. In 1984, Hadlock and colleagues developed logarithmic regression formulas based on extensive clinical data that are still widely used today. Since then, various scholars have proposed estimation models with different parameter combinations. This calculator integrates the Hadlock 4-parameter, Hadlock 3-parameter (BPD-AC-FL), Shepard, Warsof, and standard formulas commonly used in Chinese obstetrics. You can select or compare the results of different formulas above.
The core concept of ultrasound fetal weight estimation is that fetal weight is closely related to head size, trunk thickness, and thigh length. When these dimensions are combined using specific mathematical relationships, they correlate highly with actual birth weight. Taking the classic Hadlock 4-parameter formula as an example:
log10(Weight) = 1.3596 − 0.00386 × AC