Waist–hip ratio
The waist-hip ratio or waist-to-hip ratio (WHR) is the dimensionless ratio of the circumference of the waist to that of the hips.
This is calculated as waist measurement divided by hip measurement (W ÷ H). For example, a person with a 30″ () waist and 38″ () hips has a waist-hip ratio of about 0.78.
Waist-to-height ratio
A WHtR of over 0.5 is critical and signifies an increased risk; a 2010 systematic review of published studies concluded that "WHtR may be advantageous because it avoids the need for age-, sex- and ethnic-specific boundary values". For people under 40 the critical value is 0.5, for people aged 40–50 the critical value is between 0.5 and 0.6, and for people over 50 the critical values start at 0.6. 
As a comparative, the following table categorises the boundaries of persons in terms of health: