The visceral fat rating is not measured directly by the device but it's estimated in cm².

The 'gold standard' for estimating visceral fat is MRI based on a 2 dimensional 'cut' of the abdominal area (see picture of an MRI scan with visceral fat below).

Relative to MRI, 1 in our visceral fat rating index corresponds with 10 cm² visceral fat on a MRI scan.

The estimation of the amount of visceral fat is based on all the data the scale collects while measuring the body composition, as well as the variables like your height, age and gender.
The scale gives a rating between 1 and 59 for visceral fat. Between 1 and 12 the amount of visceral fat is considered as a healthy level, and from 13 to 59 is considered as too high.