The Body Mass Index (BMI) regarding ideal weight is not always meaningful. specially for a certain groups, such as athelets, pregnant women, children, and people over 65 years old. it's simply not accurate or useful.
# Waist to Hip Ration (WHR)
(WHR) is the ratio of the circumference of the waist to that of the hips. It is calculated by measuring the smallest circumference of the natural waist, usually just above the belly button, and dividing by the hip circumference at its widest part of the buttocks or hip. for example if Waist=93 and Hip=100 .. then (93/100)= .93 Indicator of health WHR is used as a measurement of obesity, which in turn is a possible indicator of other more serious health conditions. The WHO states that abdominal obesity is defined as a waist–hip ratio above 0.90 for males and above 0.85 for females, The National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK) states that women with waist–hip ratios of more than 0.8, and men with more than 1.0, are at increased health risk because of their fat distribution.
It's in Centimetres not inches.