Free Tool
HubFit's free Body Fat Calculator accurately estimates your body fat percentage using the US Navy Method. Stop relying on BMI and get instant insights into your lean muscle mass, fat mass, and overall health status.
How to Use This Body Fat Calculator
Getting an accurate body fat reading requires precise measurements. For the best results, use a flexible tape measure and follow these steps:
Select Your Unit System: Choose between Metric (kg/cm) or Imperial (lbs/in).
Enter Personal Details: Input your age, gender, height, and weight.
Measure Your Neck: Place the tape measure around your neck, just below your larynx (Adam's apple). Keep the tape flat but not tight.
Measure Your Waist:
Men: Measure at the navel level.
Women: Measure at the narrowest point of the waist, usually halfway between the lowest rib and the top of the hip bone.
Measure Your Hips (Women Only): Place the tape measure around the widest part of your hips and buttocks.
Click Calculate: Instantly see your body fat percentage, lean mass, and health category.
How to Use This Body Fat Calculator
Getting an accurate body fat reading requires precise measurements. For the best results, use a flexible tape measure and follow these steps:
Select Your Unit System: Choose between Metric (kg/cm) or Imperial (lbs/in).
Enter Personal Details: Input your age, gender, height, and weight.
Measure Your Neck: Place the tape measure around your neck, just below your larynx (Adam's apple). Keep the tape flat but not tight.
Measure Your Waist:
Men: Measure at the navel level.
Women: Measure at the narrowest point of the waist, usually halfway between the lowest rib and the top of the hip bone.
Measure Your Hips (Women Only): Place the tape measure around the widest part of your hips and buttocks.
Click Calculate: Instantly see your body fat percentage, lean mass, and health category.
Why Measure Body Fat Instead of BMI?
Many people rely on the Body Mass Index (BMI) to gauge their health, but BMI is fundamentally flawed for active individuals. It only looks at height and weight, ignoring what that weight is made of.
The "Skinny Fat" Problem: You can have a "normal" BMI but have low muscle mass and high body fat, putting you at risk for metabolic issues.
The "Overweight" Athlete: You can have a high BMI due to muscle mass, even if you are very lean.
Our Body Fat Calculator solves this by distinguishing between Fat Mass and Lean Body Mass. This gives you a true picture of your metabolic health and progress.
Understanding the Science: The US Navy Method
his tool uses the US Navy Circumference Method, a widely respected formula used by the Department of Defense to assess the fitness of service members.
Unlike calipers (which require skill to use) or bioimpedance scales (which are affected by hydration), the US Navy Method relies on body geometry. By comparing the circumference of your waist and neck (and hips for women) against your height, it estimates your body density with surprising accuracy.
How to Use the Results for Training
Male body fat percantage
Essential fat from 2% to 5%
Athletic ranges from 6% to 13%
Fitness ranges from 14% to 17%
Average ranges from 18% to 24%
Obese starts at twenty five percent and above
Female body fat percentage
Essential fat from 10% to 13%
Athletic ranges from 14% to 20%
Fitness ranges from 21% to 24%
Average ranges from 25% to 31%
Obese starts at 32% and above
Navy Body Fat Formulas Explained
The Navy method estimates your body fat by comparing your key body measurements to your height. Because men and women store fat differently, the formulas are slightly different.
How the Formula Works
The equation uses logarithms to understand the relationship between your measurements. This allows the formula to estimate how much of your total weight comes from stored fat versus lean tissue.
Waist and hip measurements are strong indicators of fat distribution. Neck and height measurements help balance the equation to give a reliable estimate.
When entered correctly, the Navy method provides one of the most accurate at home body fat estimates available.
Formula for Men
The male equation uses waist, neck and height. Measurements can be taken in either metric units or US customary units.
Metric Formula (centimeters)
BFP = 495 ÷ (1.0324 minus 0.19077 × log10(waist minus neck) plus 0.15456 × log10(height)) minus 450
US Units (inches)
BFP = 86.010 × log10(abdomen minus neck) minus 70.041 × log10(height) plus 36.76
Formula for Women
Because women naturally carry more essential fat and more fat around the hips, the female formula includes the hip measurement.
Metric Formula (centimeters)
BFP = 495 ÷ (1.29579 minus 0.35004 × log10(waist plus hip minus neck) plus 0.22100 × log10(height)) minus 450
US Units (inches)
BFP = 163.205 × log10(waist plus hip minus neck) minus 97.684 × log10(height) minus 78.387
Why This Method Is Trusted
The Navy formulas were developed and tested on thousands of individuals. Although no at home method is perfect, this is one of the most reliable options available without specialised equipment such as DEXA or hydrostatic weighing.
It provides consistent results and is ideal for tracking changes over time when measurements are taken using the same technique.
What is FFMI? (Fat-Free Mass Index)
Our calculator also provides your FFMI. Think of this as "BMI for bodybuilders."
FFMI measures how much muscle you have relative to your height, independent of how much fat you carry.
18-20: Average muscularity.
20-22: Above average (Common for natural gym-goers).
22-25: Excellent (Natural limit for most people).
25+: Superior (Rarely achievable naturally without elite genetics).
Use FFMI to track if you are actually building muscle during a bulk, or just gaining weight.
HubFit Overview
HubFit is the all-in-one coaching platform that makes it easy to build, scale, and automate your fitness business while staying fast and never feeling clunky. ⚡️
Watch our overview to see how it works.
