Waist — Waist circumference measured at the narrowest point. Use a flexible tape, exhale normally. Example: 0.1.

Waist is required

Neck — Health measurement. Use consistent units and calibrated tools for reliable tracking. Example: 0.1.

Neck is required

Height — Your height. Small errors change the outcome noticeably (height is squared in many formulas). Measure standing straight. Example: 0.1.

Height is required