--- title: "Body Fat Calculator | Method Calculator" description: "Estimate body fat percentage with the U.S. Navy method using neck, waist and hip measurements, plus a BMI-based estimate and fat category." canonical_url: "https://methodcalculator.com/body-fat-calculator" meta: "og:description": "Estimate body fat percentage with the U.S. Navy method using neck, waist and hip measurements, plus a BMI-based estimate and fat category." "og:image": "https://methodcalculator.com/_og/s/o_919d6b668fa1469a.png" "og:image:height": "600" "og:image:type": image/png "og:image:width": "1200" "og:title": "Body Fat Calculator – Free Online Tool" "twitter:image": "https://methodcalculator.com/_og/s/o_919d6b668fa1469a.png" --- > Index of every page on this site: [llms.txt](https://methodcalculator.com/llms.txt) # **Body Fat Calculator** Estimate your body fat percentage with a tape measure using the U.S. Navy circumference method, compare it with a BMI-based estimate, and see your fat and lean mass. ## **Result** Body fat (U.S. Navy method) **16.9%**
Category
**Fitness**
Fat mass
11.9 kg
Lean body mass
58.1 kg
Body fat (BMI method)
18.1%
**Body fat categories for men (American Council on Exercise)** | **Category** | **Body fat** | | --- | --- | | Essential fat | 2% – 5% | | Athletes | 6% – 13% | | Fitness | 14% – 17% | | Average | 18% – 24% | | Obese | 25% and above | ## What is body fat percentage? Body fat percentage is the share of your total weight that is fat tissue. The rest, called lean body mass, includes muscle, bone, organs and water. Two people of the same height and weight, and therefore the same [BMI](https://methodcalculator.com/bmi-calculator), can have very different body fat levels, which is why body fat is a better indicator of fitness and health risk than weight alone. Some fat is essential: it cushions organs, stores energy and regulates hormones. ## The U.S. Navy formula Developed by the Naval Health Research Center in 1984, the method uses circumference measurements and height. With all lengths in centimeters: - Men: body fat % = 495 ÷ (1.0324 − 0.19077 × log₁₀(waist − neck) + 0.15456 × log₁₀(height)) − 450 - Women: body fat % = 495 ÷ (1.29579 − 0.35004 × log₁₀(waist + hip − neck) + 0.22100 × log₁₀(height)) − 450 **Worked example:** a man 175 cm tall with a 38 cm neck and an 85 cm waist. Waist minus neck is 47 cm, log₁₀(47) = 1.672 and log₁₀(175) = 2.243. The denominator is 1.0324 − 0.19077 × 1.672 + 0.15456 × 2.243 = 1.0601, so body fat = 495 ÷ 1.0601 − 450 ≈ **16.9%**. At 70 kg that is 11.9 kg of fat and 58.1 kg of lean mass, placing him in the "fitness" category. ## The BMI method As a cross-check the calculator also shows the Deurenberg equation, which estimates adult body fat from BMI: body fat % = 1.20 × BMI + 0.23 × age − 10.8 × sex − 5.4, where sex is 1 for men and 0 for women. For the man in the example (BMI 22.9, age 30) it gives 18.1%. Because it cannot see where fat is stored, it tends to overestimate body fat in muscular people and underestimate it in people with little muscle. ## How to use this calculator 1. Choose units and sex, then enter your age, height and weight. 2. Measure your neck and waist (and hips for women) with a flexible tape, following the hints next to each field. 3. Read your Navy estimate, category, and fat and lean mass. Repeat monthly under the same conditions to track trends rather than single readings. ## Limitations Tape-measure methods are estimates with an error of a few percentage points; a DEXA scan or hydrostatic weighing is more precise. Results are for adults and do not apply to pregnant women or children. This calculator is for information only and is not medical advice. ## **Frequently asked questions ** ### **How accurate is the U.S. Navy body fat method?** Studies comparing it with underwater weighing and DEXA scans find a typical error of about 3 to 4 percentage points for most adults, which is comparable to consumer bioimpedance scales. It is least accurate for very lean or very obese people. Measuring carefully at the same time of day improves consistency. ### **What is a healthy body fat percentage?** According to the American Council on Exercise, 14 to 24 percent is in the fitness-to-average range for men and 21 to 31 percent for women. Women naturally carry more essential fat for hormonal and reproductive functions, which is why their ranges sit about 10 points higher. ### **Where exactly do I measure my waist, neck and hips?** Measure the neck just below the larynx with the tape sloping slightly downward at the front. Men measure the waist at the navel; women measure at the narrowest point. Hips are measured at the widest part of the buttocks. Keep the tape snug but not compressing the skin, and stand relaxed. ### **Why do the Navy and BMI methods give different numbers?** The BMI method only knows your height, weight, age and sex, so it assumes an average build. The Navy method uses waist and neck circumference, which reflect where you actually store fat. When the two disagree by a lot, the Navy estimate is usually closer for people who are muscular or carry weight around the middle. ## **Related calculators ** - [**BMI Calculator**](https://methodcalculator.com/bmi-calculator) - [**Ideal Weight Calculator**](https://methodcalculator.com/ideal-weight-calculator) - [**BMR Calculator**](https://methodcalculator.com/bmr-calculator) - [**Macro Calculator**](https://methodcalculator.com/macro-calculator) ```json {"@context":"https://schema.org","@graph":[{"@id":"https://methodcalculator.com/#website","@type":"WebSite","description":"Free online calculators for finance, health and fitness, math and everyday life. 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