Body Fat Percentage Calculator: US Navy Method for Accurate Results
Use three tape measurements—waist, neck, and (for women) hip—plus height to estimate body-fat with the U.S. Navy formula. Healthy ranges sit between 14-24 % for men and 21-31 % for women (ACE, 2019). Enter your data, hit “Calculate,” and the script returns a percentage within ±4 % of DXA scans (Hodgdon & Beckett, 1984).
Body Fat Percentage Calculator
Your Body Fat Percentage:
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How to use the tool
Select gender—pick Male or Female.
Measure height in centimetres using a wall-mounted ruler. Examples: 168 cm, 191 cm.
Wrap a flexible tape around the navel for waist, around the narrowest point for neck, and (women) around the widest hip point. Sample sets:
• Male: waist 92 cm, neck 38 cm
• Female: waist 70 cm, neck 34 cm, hip 98 cm
Press “Calculate.” The percentage appears instantly.
Male: height 178 cm, waist 92 cm, neck 38 cm ⇒ 21.8 %
Female: height 165 cm, waist 70 cm, neck 34 cm, hip 98 cm ⇒ 25.4 %
Quick-Facts
Healthy body-fat range: men 14-24 %, women 21-31 % (ACE, 2019).
U.S. Navy formula accuracy ±3-4 % of DXA (Hodgdon & Beckett, 1984).
Tape measure costs under $10 at major retailers (Amazon product page, 2024).
“Circumference sites shall be measured to the nearest 0.25 inch” (SECNAVINST 6110.1H).
FAQ
What is body-fat percentage?
Body-fat percentage shows how much of your weight is fat mass versus lean tissue, giving a clearer health picture than BMI (CDC, 2022).
How does the calculator work?
It plugs your measurements into the U.S. Navy logarithmic equations, then subtracts 450 to output a percentage—no personal data stored (U.S. Navy Body Composition Program, 2023).
Why use log10 in the formula?
Logarithms linearise the relationship between body girths and density, improving fit across body sizes (Hodgdon & Beckett, 1984).
How accurate is the result?
The Navy method stays within ±4 % of gold-standard DXA for most adults, but athletes or very obese users may see wider error (Jackson et al., 2002).
How often should you measure?
Take readings every 4-8 weeks; shorter intervals rarely show real composition change (ACE, 2019).
What equipment do you need?
A cheap centimetre tape and a mirror to keep the tape horizontal—no scales or calipers needed.
Female fat distribution centres on the gluteal-femoral region; adding hip girth raises equation accuracy by ~3 % (Friedl, 1992).
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