How to Calculate Body Fat Percentage
6 min read · Updated September 26, 2026 · by the SolveCalcPro editorial team
Body fat percentage separates fat from lean mass, which weight and BMI cannot do. The US Navy method estimates it using a tape measure. This guide shows how to measure, how the formula works and how to interpret the result.
What you need to measure
- Height, standing barefoot.
- Neck, just below the larynx.
- Waist: men at the navel, women at the narrowest point.
- Hips (women only), at the widest point.
Measure three times and average; keep the tape snug but not tight.
The formula
In centimetres: men — 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450; women — 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.221 × log₁₀(height)) − 450. It estimates body density from circumferences, then converts to percent fat.
Worked example
A man 5 ft 10 in with a 15 in neck and 34 in waist: 17.4% (Fitness). With a 32 in waist: 13.4%. Waist is the most sensitive input.
Interpreting the result
| Category | Women | Men |
|---|---|---|
| Essential fat | 10–13% | 2–5% |
| Athletes | 14–20% | 6–13% |
| Fitness | 21–24% | 14–17% |
| Average | 25–31% | 18–24% |
| Above average | 32%+ | 25%+ |
The method is accurate to roughly 3–4 percentage points, so use it for trends. Not medical advice.
Practice questions
Test yourself, then tap to check. Answers are calculated by the tools linked below.
- A woman 5 ft 6 in tall, neck 13 in, waist 30 in, hips 39 in. What is her estimated body fat?
Show answer
Estimated body fat: 28.8% · Category (ACE ranges): Average
- A person weighs 82 kg and is 178 cm tall. What is their BMI and category?
Show answer
BMI: 25.9 · Category (adult WHO ranges): Overweight
- A 28-year-old woman, 62 kg, 168 cm, lightly active, wants to maintain her weight. What are her BMR and TDEE?
Show answer
Daily calorie target: 1,882 kcal · Maintenance calories (TDEE): 1,882 kcal
Frequently asked questions
How accurate is the Navy body fat method?
Within about 3–4 percentage points for most adults — good for tracking change.
Where do I measure my waist?
At the navel for men and the narrowest point for women, standing relaxed.
Is body fat percentage better than BMI?
It describes composition, so it can distinguish a muscular person from one with excess fat; BMI cannot.
What is a healthy body fat percentage?
It varies with age and sex; ACE categories show typical ranges for fitness and average.
Try it yourself
Body Fat Calculator (US Navy Method)Estimate body fat percentage from height, neck, waist (and hip) measurements in cm or inches using the US Navy method.BMI CalculatorCalculate body mass index for adults in kg/cm or lb/feet/inches, with the WHO category and the healthy weight range for your height.Calorie Calculator (TDEE, BMR & Macros)Estimate your BMR, daily calorie needs (TDEE), a calorie target for your goal and a macro split, in lb/ft or kg/cm.Keep learning
How to Calculate BMI6 min readHow to Calculate TDEE and Daily Calories7 min read
How to Convert Units6 min readWritten and reviewed by the SolveCalcPro editorial team. Spot a mistake? Tell us. See our editorial policy.