For the given set of data, the calculator will find the pth percentile, with steps shown. How calculations are based. This estimated fetal weight calculator will calculate percentiles as well as the estimated fetal weights based ultrasound data and on many published formulas, including those by Hadlock, Shepard, Woo, Shinozuka, Ott, Combs, Warsof, Campbell, and many others. This calculator provides BMI and the corresponding BMI-for-age percentile based on the CDC growth charts for children and teens (ages 2 through 19 years). Because of possible rounding errors in age, weight, and height, the results from this calculator may differ slightly from BMI-for-age percentiles calculated by other programs.