What is the Body Fat Calculator?
We offer two modes: (1) US Navy method using neck, waist, standing height, and hip (women)  a widely used field estimate; (2) BMI-based estimate using age and sex (Deurenberg-style), helpful when tape measurements are unavailable.
Why people use this calculator
Tracking body fat trends matters for fitness goals beyond scale weight. Navy method is repeatable at home with a flexible tape.
How to use the Body Fat Calculator  summary
- Pick method: Navy (measurements) or BMI-based (weight + height + age).
- Enter metrics: Follow on-screen hints for waist (at navel), neck (below larynx), hip (widest).
- Calculate: See % body fat, rough category band and your BMI for context.
Tips for best results
Use these numbers as conversation starters with a qualified professional  not as a diagnosis. Track trends over weeks, not single days.