Navy Body Fat Calculator + BMI (Tape Measure Method)

The US Navy method estimates body fat percentage from simple tape measurements: waist, neck, and (for women) hip circumference. It uses published equations that were developed for military personnel. It's a practical estimate, not as accurate as DEXA scans or professional methods.

Measure at the same time of day, ideally in the morning. Neck: measure below the larynx. Waist: measure at the narrowest point (usually at the navel level). Hips (women): measure at the widest point. Keep the tape level and snug but not tight. Consistency matters more than perfection.

No. BMI (Body Mass Index) is weight relative to height squared. Body fat percentage is the proportion of your weight that is fat tissue. They measure different things. A person can have a normal BMI but higher body fat, or a higher BMI but lower body fat (if they have more muscle mass).

The Navy body fat formula only needs height and circumference measurements. Weight is only needed if you want BMI or fat/lean mass estimates. You can get a body fat % estimate without weight.

The accuracy depends on how accurately you measure. Small measurement errors can shift the result. The Navy method is a reasonable estimate for most people but is not as accurate as DEXA scans or professional caliper measurements. Use it to track trends over time rather than obsess over a single reading.

If the body fat % is very low (<2%) or very high (>60%), double-check your measurements and units. Small differences in measurements, especially between waist and neck, can significantly affect the result. Make sure you're measuring at the correct locations.

Yes, but consistency is key. Measure at the same time of day, under similar conditions, and track trends over weeks or months rather than focusing on day-to-day changes. The estimate is more useful for seeing direction of change than for getting an exact number.

No. This calculator is for educational purposes only and is not medical advice. It does not diagnose conditions or replace professional guidance. If you have health concerns, consult a qualified healthcare provider.