A method and a system for estimating visceral fat area (VFA) of a subject uses the product of the Xth power of a height value (Ht) and the Yth power of a fat mass value (FM), through a parameter expressed as FM/Ht.sup.2 or Ht.sup.2/FM, or by using an equation expressed as VFA=C11*FM/Ht.sup.2+C12*Age+C13, where each of X and Y are a number other than zero. The method and the system decrease estimation errors due to height, thereby enabling common use by a number of nations each having a different average height, and decreasing cost of development and manufacturing.