Body Fat (US Navy): 5 Mistakes to Avoid
Estimates body fat percentage from tape measurements. The maths is not complicated, but a handful of errors come up again and again in this and related health & fitness calculations. Here is what to watch for.
Energy needs depend on age, sex, size and activity. Formulas such as Mifflin-St Jeor estimate resting needs, and an activity multiplier turns that into daily needs. Real requirements vary by a few hundred calories, so adjust based on how your weight changes over several weeks.
Any health calculator gives a general estimate. If a result worries you, or you are pregnant, managing a chronic condition or planning a big change in diet or exercise, speak to a doctor, polyclinic or dietitian.
1. Relying on a single measurement
Weight and heart rate fluctuate daily; trends tell you more.
2. Mixing units
Entering pounds or inches into a metric formula gives nonsense results.
3. Using international BMI cut-offs for Asians
HPB recommends lower cut-offs because risks rise at lower BMIs in Asian populations.
4. Ignoring hydration in hot weather
Outdoor activity in Singapore's climate increases fluid loss.
5. Cutting calories too aggressively
Very large deficits are hard to sustain and can lead to muscle loss.
The correct method
US Navy circumference formula using log10 of waist, neck (and hip) and height.
For example, with these inputs:
- Sex: Male
- Height (cm): 172
- Neck (cm): 38
- Waist (cm): 85
- Hip (cm, women only): 95
the calculator returns:
- Body fat: 17.45%
Related calculations
- Protein Intake Calculator: Estimates daily protein needs.
- Steps to Kilometres Calculator: Converts step counts (like your Healthy 365 tracker) to distance.
- Running Pace Calculator: Calculates pace for runs like the Standard Chartered Marathon or IPPT 2.4 km.
- Calories Burned Calculator: Estimates calories burned with MET values.
The Body Fat Calculator (US Navy) applies the formula consistently, so it is a quick way to double-check your own working.
Run your own numbers: Body Fat Calculator (US Navy)