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Body Fat Percentage Calculator

Estimate your body fat percentage using the US Navy Method or BMI Method. See your fat mass vs lean mass, body fat category, and a clear visual body fat scale — for men and women.

✅ Navy & BMI methods ✅ Fat mass vs lean mass ✅ 5 categories (ACE standard) ✅ Visual body fat scale
Last updated: March 2026

📝 Enter Your Measurements

Navy Method needs height + neck + waist (+ hip for women). Add weight & age for fat mass and BMI method results.

Affects body fat category ranges and hip measurement requirement.
Please enter a valid age (15–100).
Please enter a valid height (100–250 cm).
Please enter a valid weight (20–400 kg).
Measure below the larynx (Adam's apple), sloping slightly downward.
Please enter a valid neck size (20–70 cm).
Measure at the navel (belly button), relaxed — do not suck in.
Please enter a valid waist size (40–200 cm).
Navy Method — uses height + neck + waist (+ hip for women).
BMI Method — needs weight + age too. Fill all fields to compare both.

Results & Body Composition

Results update as you type. Navy Method is primary; BMI Method appears when weight + age are provided.

👈 Enter your measurements to calculate body fat %

Required: height + neck + waist (+ hip for women)
📌 Why body fat % matters more than weight alone

Know your fat mass — not just the number on the scale

Two people can have the same weight but completely different body compositions. Body fat percentage gives you a clearer picture of your health, fitness level, and metabolic risk — helping you make smarter decisions about training, nutrition, and long-term wellness.

What Is Body Fat Percentage?

Body fat percentage is the proportion of your total body weight that is made up of fat tissue. It distinguishes between your fat mass (adipose tissue) and your lean mass — which includes muscles, bones, organs, connective tissue, and water.

Unlike BMI (which only considers height and weight), body fat percentage accounts for body composition, making it a more informative metric for fitness and health risk assessment. An athlete and a sedentary person can have the same BMI but very different body fat percentages.

How to Use This Body Fat Calculator

  1. Choose your unit system (Metric or Imperial).
  2. Select your biological sex — women need an additional hip measurement for the Navy Method.
  3. Enter height, neck circumference, and waist circumference. These are the minimum required inputs for the Navy Method.
  4. (Women only) Enter your hip circumference at its widest point.
  5. (Optional) Enter weight and age to also get the BMI Method result and your fat/lean mass breakdown.
  6. Read your results: body fat %, category, visual scale, and personalized recommendations.
Measuring tips: Use a flexible soft tape measure. Stand relaxed, breathe normally, and don't suck in or flex. Measure directly against skin for best accuracy.

How Body Fat Is Calculated

US Navy Method

The US Navy Method uses body circumference measurements (neck, waist, and hip) along with height. It uses validated logarithmic formulas developed and used by the US military for field body fat assessment.

Men: BF% = 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450

Women: BF% = 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450

Typical accuracy: ±3–4% compared to DEXA scan.

BMI Method (Deurenberg)

The BMI Method (Deurenberg et al., 1991) estimates body fat percentage from BMI, age, and sex. It requires weight, height, and age.

Formula: BF% = (1.20 × BMI) + (0.23 × Age) − (10.8 × sex) − 5.4

Where sex = 1 for males, 0 for females.

Typical accuracy: ±5–6%. Less reliable for muscular individuals.

Body Fat Percentage Categories (ACE Guidelines)

Men

CategoryBody Fat %What it means
Essential Fat2–5%Minimum for survival
Athletic6–13%Typical competitive athlete
Fitness14–17%Lean, active individual
Acceptable18–24%Average, not high risk
Obese≥ 25%Elevated health risk

Women

CategoryBody Fat %What it means
Essential Fat10–13%Minimum for survival
Athletic14–20%Typical competitive athlete
Fitness21–24%Lean, active individual
Acceptable25–31%Average, not high risk
Obese≥ 32%Elevated health risk

Source: American Council on Exercise (ACE). Categories are general guidelines; individual health risk should be assessed by a clinician.

Frequently Asked Questions

For men, the fitness range (14–17%) is generally considered healthy and active. The acceptable range (18–24%) is not a risk zone but suggests room for improvement. For women, fitness range is 21–24% and acceptable is 25–31%. These are ACE guidelines — individual context matters.
The US Navy Method (also called the circumference method) estimates body fat using a tape measure to record neck, waist, and (for women) hip circumferences, along with height. It uses validated logarithmic formulas developed for practical field use by the US military.
The Navy Method typically has a margin of error of ±3–4% when compared to DEXA scan (the gold standard). It is one of the most practical and reliable field methods for estimating body fat without specialized equipment. Measurement consistency (same time of day, same technique) improves repeatability.
Fat mass is the total weight of all fat tissue in your body (both essential fat and storage fat). Lean mass (or fat-free mass) is everything else — muscles, bones, organs, connective tissue, and body water. Increasing lean mass through resistance training improves metabolism, strength, and overall body composition.
For men, 20% falls in the "acceptable" range (18–24%). It is not a health risk by itself but is above the fitness range (14–17%). Most men who want to look lean and feel athletic aim for the fitness category. Small consistent changes in diet and exercise can bring it down over time.
According to ACE guidelines: ≥25% body fat for men and ≥32% body fat for women is classified as obese. This is associated with increased risk of metabolic syndrome, cardiovascular disease, and type 2 diabetes. Professional guidance is recommended at this range.
Measure your waist horizontally at the level of your navel (belly button). Stand relaxed, breathe normally, and do not suck in your stomach or flex. Keep the tape snug but not compressing the skin. For consistent results, always measure at the same time of day (morning, before eating, is common).
Yes — this is called body recomposition and it is possible, especially for beginners, people returning after a break, and those with higher body fat levels. It requires a moderate calorie deficit (or maintenance), high protein intake (1.6–2.2g per kg of bodyweight), and consistent progressive resistance training. Progress is slower than focusing on one goal at a time, but it is achievable.