US Navy Method

Body Fat Calculator

Enter your measurements — your body fat percentage and composition update instantly as you type.

Your gender
Your height
Please enter a valid height (100–250 cm).
Your weight
Please enter a valid weight.
Your waist circumference — measured at navel
Please enter a valid waist circumference.
Your neck circumference — at narrowest point
Please enter a valid neck circumference.
Your body composition
Body Fat Percentage
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—
Fat Mass
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kg
Lean Body Mass
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kg
BMI
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kg/m²
ACE Body Fat Category
Results are estimates for informational purposes only. Not medical advice. Consult a healthcare professional for personalized guidance.

What is Body Fat Percentage?

Body fat percentage represents the total proportion of your body weight that consists of fat. It is a key metric for assessing overall health, fitness level, and body composition. Unlike weight alone, body fat percentage tells you how much of your mass is fat versus lean tissue such as muscle, bone, and organs.

The US Navy Method

The US Navy Method is a widely used formula developed by the United States Navy for estimating body fat using simple circumference measurements and height. It was published by Hodgdon and Beckett in 1984 and remains one of the most practical and accessible estimation methods available.

Male Formula:
BF% = 86.010 × log10(waist_cm − neck_cm) − 70.041 × log10(height_cm) + 36.76

Female Formula:
BF% = 163.205 × log10(waist_cm + hip_cm − neck_cm) − 97.684 × log10(height_cm) − 78.387

Step-by-Step Example

Consider a male with the following measurements: height 180 cm, weight 85 kg, waist 88 cm, neck 38 cm.

Step 1: Calculate waist minus neck: 88 − 38 = 50 cm

Step 2: log10(50) = 1.6990

Step 3: log10(180) = 2.2553

Step 4: Apply the male formula:

BF% = 86.010 × 1.6990 − 70.041 × 2.2553 + 36.76

BF% = 146.13 − 157.93 + 36.76

BF% = 24.96% (approximately 25.0%)

Step 5: Fat mass = 85 × 0.2496 = 21.2 kg

Step 6: Lean body mass = 85 − 21.2 = 63.8 kg

How Body Fat Connects to Your TDEE

Your Total Daily Energy Expenditure (TDEE) is the number of calories you burn each day. Most TDEE formulas, such as Mifflin-St Jeor, estimate your Basal Metabolic Rate (BMR) using only height, weight, age, and gender. However, these formulas cannot account for individual differences in body composition.

This is where body fat percentage becomes valuable. When you know your body fat percentage, you can calculate your lean body mass and use the Katch-McArdle formula:

BMR = 370 + (21.6 × lean_body_mass_kg)

Because Katch-McArdle is based on lean mass rather than total weight, it provides a more accurate BMR estimate for people who are particularly muscular or who carry more body fat than average. This BMR is then multiplied by an activity factor to get your TDEE.

Use our TDEE Calculator to find your daily calorie needs using your body fat data for a more personalized result.

Related Calculators

TDEE Calculator
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BMR Calculator
Lean body mass is the biggest driver of your BMR — more muscle means more calories burned at rest.
Calorie Deficit Calculator
Use your TDEE to set a precise daily calorie deficit for steady, sustainable fat loss.
Macro Calculator
Higher body fat calls for higher protein targets to preserve muscle while cutting.
Our Methodology
See exactly how the US Navy Method formula works and why we chose it for this calculator.
What Is TDEE?
Understand how your daily calorie needs are calculated — and how body composition feeds into it.

Frequently Asked Questions

What is body fat percentage? +
Body fat percentage is the proportion of your total body weight that is made up of fat tissue. It includes both essential fat (needed for normal physiological function) and storage fat (energy reserves stored in adipose tissue). Unlike BMI, body fat percentage distinguishes between fat mass and lean mass, giving a more accurate picture of body composition.
How is body fat calculated using the US Navy Method? +
The US Navy Method estimates body fat percentage using circumference measurements. For men, the formula uses waist and neck circumference along with height: BF% = 86.010 × log10(waist − neck) − 70.041 × log10(height) + 36.76. For women, hip circumference is also required: BF% = 163.205 × log10(waist + hip − neck) − 97.684 × log10(height) − 78.387. All measurements are in centimeters.
What is a healthy body fat percentage? +
Healthy body fat ranges differ by gender. According to the American Council on Exercise (ACE), healthy ranges are: Men — Athletes 6–13%, Fitness 14–17%, Average 18–24%. Women — Athletes 14–20%, Fitness 21–24%, Average 25–31%. Essential fat minimums are 2–5% for men and 10–13% for women. Body fat above 25% for men or 32% for women is classified as obese.
What is the difference between body fat percentage and BMI? +
BMI (Body Mass Index) is calculated solely from height and weight and does not distinguish between fat and muscle. A muscular person can have a high BMI but low body fat. Body fat percentage directly measures the proportion of fat in your body, making it a more accurate indicator of health and fitness. However, BMI is simpler to calculate and useful for population-level health screening.
How accurate is the US Navy body fat formula? +
The US Navy Method is generally accurate within 1–3% of more precise methods like DEXA scans for most people. It tends to be most accurate for individuals with average body compositions. It may be less accurate for very lean athletes or individuals with very high body fat. Despite its limitations, it is one of the most accessible and widely validated circumference-based methods available.
What is lean body mass? +
Lean body mass (LBM) is everything in your body that is not fat — including muscles, bones, organs, water, and other tissues. It is calculated by subtracting fat mass from total body weight. Knowing your lean body mass is valuable for setting nutrition goals, calculating protein needs, and using formulas like Katch-McArdle to estimate your Basal Metabolic Rate more accurately.