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Home› Health Calculators› Body & Fitness› Body Fat Percentage Calculator

Body Fat Percentage Calculator
with US Navy & BMI Method

Estimate body fat percentage using body measurements and compare the US Navy method with a BMI-based estimate. Supports metric and imperial input.

📏
Body Fat Percentage Calculator
⚥
Required because the US Navy method and category ranges differ for male and female values.
yrs
Used in the BMI-based body fat estimate and for result context.
Metric inputs
cm
Standing height in centimetres.
kg
Current body weight in kilograms.
cm
Waist circumference in centimetres.
cm
Neck circumference in centimetres.
cm
Hip circumference is required for female US Navy body fat calculation.
Imperial inputs
ft
Feet part of height.
in
Inches part of height.
lb
Current body weight in pounds.
in
Waist circumference in inches.
in
Neck circumference in inches.
in
Hip circumference is required for female US Navy body fat calculation.
Method note
This calculator shows two estimates. The US Navy method uses body measurements. The BMI method uses BMI, age, and sex. They may not match exactly.
US Navy Body Fat
—
body measurement estimate
BMI Method
—
BMI-based body fat estimate
Body Fat Category
—
general category using US Navy result
Fat Mass
—
estimated fat mass from US Navy result
Lean Mass
—
estimated lean mass from US Navy result
US Navy
Calculated from circumference measurements and height.
BMI Method
—
Calculated from BMI, age, and sex-based adjustment.
Input summary
Height used—
Weight used—
Waist used—
Neck used—
Hip used—
Context
Sex—
Age—
BMI—
Category—
Difference between methods—
General Body Fat Categories
Sex Essential Athletic Fitness Average Higher
Body Fat Calculation Breakdown
Unit system—
Sex—
Age—
Body Mass Index—
US Navy body fat—
BMI method body fat—
Difference between methods—
Fat mass—
Lean mass—
Category—
This calculator provides estimation methods and is not medical advice. Body fat methods can differ depending on hydration, measurement technique, and formula choice.
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💡 Body Fat Notes

The US Navy method uses body measurements and tends to be more measurement-sensitive than a BMI-only estimate.
The BMI body fat estimate is convenient but less individualized than a circumference-based method.
Fat mass is body weight multiplied by body fat percentage.
Lean mass is body weight minus estimated fat mass.
Body fat categories are broad reference bands, not diagnoses.

Related Calculators

BMI Calculator→ Lean Body Mass Calculator→ Waist to Height Ratio Calculator→ Ideal Weight Calculator→ Protein Calculator→

Related Guides

Body Fat Methods Explained→ US Navy Body Fat Formula→ Body Fat vs BMI→

How body fat percentage is estimated here

This calculator shows two body fat estimates. The first is the US Navy method, which uses body measurements and height. The second is a BMI-based equation that uses BMI, age, and sex.

Because these methods rely on different inputs, they can return different values for the same person. That is normal. The purpose here is comparison and structured estimation, not diagnosis.

Core formulas

Fat Mass = body weight × body fat percentage
Lean Mass = body weight − fat mass
BMI = body weight ÷ height²
US Navy body fat uses logarithmic circumference formulas. BMI method body fat uses a BMI-based estimate adjusted for age and sex.

US Navy method vs BMI method

The US Navy method uses body measurements and height, so it reacts directly to changes in waist, neck, and in female calculations, hip circumference. The BMI method uses BMI, age, and sex, so it does not account for circumference differences directly.

That makes the US Navy estimate more measurement-dependent, while the BMI method is faster but broader.

Method Main Inputs What It Emphasizes
US NavyHeight, waist, neck, and female hipBody measurements
BMI MethodHeight, weight, age, sexBody size and age adjustment

How categories are used

The category labels shown here are broad reference groups such as essential, athletic, fitness, average, and higher. They are meant for general interpretation only. They do not replace a professional assessment or a medical standard.

Because category cutoffs vary by source, the ranges shown here should be treated as general-use reference bands.

Frequently Asked Questions

Why do the US Navy and BMI methods differ?+
Because they use different inputs. The US Navy method uses circumference measurements, while the BMI method uses BMI, age, and sex. Different inputs often lead to different estimates.
What is fat mass?+
Fat mass is the estimated portion of total body weight that comes from body fat. It is calculated by multiplying body weight by body fat percentage.
What is lean mass?+
Lean mass is total body weight minus estimated fat mass. It includes everything that is not estimated body fat within this simplified calculation.
Why is hip circumference only required for female US Navy calculation?+
Because the common female US Navy formula includes hip circumference, while the common male version uses waist and neck relative to height without hip circumference.
Are these results exact?+
No. They are estimation methods. Measurement error, hydration, body shape, and formula choice can all affect the result.