Is visceral_fat_level a percentage?

visceral_fat_level is the raw numeric index passed through from the scale device.

visceral_fat_level is the raw numeric index passed through from the scale device. It is not a percentage and there is no formula to derive one.

Its scale is provider-specific (for example Withings roughly 0-20, Omron 1-30), so the same number means different things across providers.

For a comparable value, use visceral_fat_category, which Terra normalises into NORMAL / HIGH / VERY_HIGH using each provider's published thresholds.