Body Fat Calculator
Estimate your body-fat percentage using height and body circumference measurements. This calculator uses the U.S. Navy circumference method and also estimates fat mass and lean body mass. Choose metric or imperial measurements and enter your details below.
Enter Your Measurements
For more consistent results, use a flexible measuring tape and measure each circumference without pulling the tape excessively tight.
Body Fat Position
The marker gives a simple visual indication of your estimated percentage. Classification differs by sex, age and source.
Measurement Summary
The Navy method uses different circumference inputs for males and females.
How to Take the Measurements
Use a flexible tape measure. Keep the tape level and snug against the body without compressing the skin.
Measure around the neck below the larynx, keeping the tape approximately level and relaxed.
Measure around the waist or abdominal area according to the selected method, without pulling the stomach in.
Measure around the widest part of the hips and buttocks, keeping the tape level.
How to Use the Body Fat Calculator
Choose metric or imperial measurements and select the sex used by the calculation formula. Then enter your height, body weight, neck circumference and waist circumference.
For the female Navy formula, the calculator also asks for hip circumference.
The calculator estimates:
- Body-fat percentage;
- Fat mass;
- Lean body mass;
- A general body-fat category; and
- Your approximate position on a body-fat scale.
What Is Body Fat Percentage?
Body-fat percentage is the estimated proportion of total body weight that consists of fat tissue.
For example, if a person weighs 80 kg and has an estimated body-fat percentage of 20%, the simplified estimated fat mass is:
The remaining weight is often described as fat-free or lean body mass, although actual body composition is more complex.
What Method Does This Body Fat Calculator Use?
This calculator uses the circumference method commonly associated with the U.S. Navy body-fat estimation formula.
It estimates body composition using height and selected circumference measurements rather than requiring specialist equipment.
Male Body Fat Formula
For males, the method uses:
- Height;
- Neck circumference; and
- Waist or abdominal circumference.
The calculation is based on the relationship between waist minus neck circumference and height.
Female Body Fat Formula
For females, the Navy circumference method uses:
- Height;
- Neck circumference;
- Waist circumference; and
- Hip circumference.
The additional hip measurement reflects the different formula used for female body-fat estimation.
Body Fat Percentage vs BMI
Body-fat percentage and BMI are different measurements.
BMI
BMI uses only height and weight.
Body-fat percentage
Body-fat percentage attempts to estimate how much of body weight is fat rather than lean tissue.
A muscular person can have a relatively high BMI while having a comparatively low body-fat percentage.
For BMI, use the BMI Calculator.
What Is Lean Body Mass?
Lean body mass is estimated by subtracting fat mass from total body weight.
It includes muscle, bone, organs, water and other non-fat body components.
How Is Fat Mass Calculated?
For example, someone weighing 75 kg at an estimated 18% body fat would have:
75 × 0.18 = 13.5 kg estimated fat mass
How Accurate Is a Body Fat Calculator?
Circumference-based body-fat calculators provide estimates rather than direct measurements.
Results can vary because of:
- Measurement technique;
- Tape placement;
- Body shape;
- Muscularity;
- Hydration;
- Individual fat distribution; and
- Limitations of the underlying formula.
Taking measurements in the same way and under similar conditions can make repeat results more useful.
Body Fat Percentage Categories
There is no single classification system appropriate for every person. Body-fat ranges vary by sex, age, athletic status and the reference used.
The category shown by this calculator is intentionally broad and should be treated as an informational guide rather than a health diagnosis.
Is Low Body Fat Always Better?
No. Body fat performs important physiological functions, including energy storage, insulation and support for normal hormonal and cellular processes.
Extremely low body-fat levels may not be suitable or sustainable for many people.
Why Does Body Fat Differ Between Men and Women?
Average body-fat distribution and essential fat requirements differ between males and females because of biological and hormonal differences.
For this reason, body-fat classification ranges and circumference formulas are generally sex-specific.
Can I Calculate Body Fat Without Calipers?
Yes. Circumference methods such as the one used here require only a tape measure.
Other body-composition methods include:
- Skinfold calipers;
- Bioelectrical impedance scales;
- DEXA scans;
- Hydrostatic weighing; and
- Air-displacement methods.
Body Fat Scale vs Circumference Calculator
Consumer body-fat scales commonly use bioelectrical impedance, while this calculator uses body measurements.
Both methods are estimates and can produce different results.
Rather than comparing values from unrelated methods, it is often more useful to use the same method consistently when tracking changes over time.
How Often Should I Measure Body Fat?
Because body measurements and hydration can vary from day to day, very frequent measurements may create unnecessary noise.
For trend tracking, repeat measurements under similar conditions and focus on changes over time rather than small day-to-day differences.
Body Fat and Weight Loss
Changes in scale weight do not always correspond directly to changes in body fat.
Weight can also change because of:
- Water;
- Glycogen;
- Food intake;
- Muscle mass; and
- Other normal body fluctuations.
Body weight, waist measurement and body-fat estimates can therefore provide different types of information.
Can Body Fat Be Used to Calculate Calories?
Some energy equations can use lean body mass when estimating resting metabolic rate, but this calculator is designed specifically to estimate body composition.
For daily energy needs, use the TDEE Calculator.
Body Fat Calculator Assumptions
This calculator:
- Uses a circumference-based Navy estimation method;
- Uses different formulas for male and female selections;
- Converts metric measurements to inches internally for the equation;
- Uses body weight only to estimate fat mass and lean mass;
- Assumes measurements are taken consistently;
- Does not directly measure body fat;
- Does not adjust for age;
- Does not account directly for muscularity or bone structure;
- Is intended primarily for adults; and
- Does not provide a medical diagnosis.
Related Health & Fitness Calculators
Body Fat Calculator FAQs
How do I calculate body-fat percentage at home?
One simple approach is a circumference-based formula using measurements such as height, neck, waist and, for the female Navy formula, hip circumference.
What is the Navy body-fat method?
It is a circumference-based estimation method that uses body measurements and height to estimate body-fat percentage.
Is body-fat percentage the same as BMI?
No. BMI uses height and weight only, while body-fat percentage attempts to estimate the proportion of body weight that is fat.
What is lean body mass?
Lean body mass is the estimated body weight remaining after estimated fat mass is subtracted from total weight.
Is the Navy body-fat formula completely accurate?
No. It provides an estimate and can differ from direct or laboratory body-composition measurements.
Why does the female formula require hip measurement?
The female Navy circumference equation includes hip circumference together with waist, neck and height measurements.
Can I use this calculator to track progress?
Yes. Using the same measurement technique under similar conditions can make the calculator useful for observing approximate trends over time.