§ · Body Fat (US Navy)
US Navy bodyfat calculator.
Three to four circumference measurements. Two minutes with a tape measure. A reasonable body-fat estimate without DEXA.
§ · Calculator
US Navy circumference method86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76
§ 01 · How to measure
Neck: just below the larynx, parallel to the floor. Stand relaxed.
Waist:men measure at the navel; women measure at the narrowest point. Don't suck in.
Hip (women): the widest point of the hips, parallel to the floor.
Use a soft tape measure (cloth or vinyl). Pull snug but don't compress the tissue. Take each measurement three times and use the median if they disagree by more than a centimetre.
§ 02 · The formula
Men: 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76
Women: 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387
All measurements in centimetres. The calculator handles unit conversion when you pick inches.
This is an estimate, not DEXA. Expect to be within ±3% of the actual number for most body types. The estimate gets less reliable at the extremes (very lean, very obese).
§ 03 · How BiteDeck uses this
In the app, saved BF% entries feed two places: the Home Composition page (the visible chart) and the Katch–McArdle BMR used by the weight forecast. You only have to enter it once — the app remembers and uses it daily.
§ 04 · Other methods we support
BiteDeck supports four BF estimation paths in the app:
- US Navy (this calculator).
- Deurenberg (BMI + age + sex).
- Manual entry (DEXA, calipers, scale, whatever).
- HealthKit import (from a connected scale or another app).
Now that you have a number, plug it into the Katch–McArdle BMR calculator for a body-fat-aware metabolic rate.